Alex makes an offer to Bob, but he rejects it. Later, Bob changes his mind and decides to take the offer after all, but Alex refuses to extend the offer a second time. It is Off the Table.
If Bob is the protagonist, this is usually portrayed as being out of spite or Evil Gloating on Alex's part. If Alex is the protagonist, this is usually portrayed as righteous indignation and/or a deserved comeuppance to Bob. Sometimes the original offer is Off the Table but Alex will allow Bob to accept a modified version with more conditions and/or a higher cost, to drive home the lesson that Bob should have taken what was offered when he had the chance. And other times the offer is withdrawn without any good or ill intent: there was a time or a place where it could be accepted but now that opportunity has passed.
In any case, the moral of the story is this: If you refuse an offer, for whatever reason, there are no guarantees you can accept it later if you change your mind.
This occasionally occurs as an aversion of Sweet and Sour Grapes. Related to Last-Second Chance and Heel Face Door Slam, if the villain is offered one more chance to repent and either refuses or accepts too late.
Monsters vs. Aliens: After Susan turns into a 50-foot woman (well, 49-foot, 11 and 1/2-inch woman) on what was to be her wedding day, her fiance breaks it off with her. Later, after she helps save the world, he offers to "forgive" her and take her back (largely to further his own career as a newscaster). Cue the (much deserved) Humiliation Conga.
Buffy got in a rebound relationship after Angel left. The guy, Parker, dumped her after they slept together, and Buffy got depressed. When she gets turned into a cavewoman, she saves his life (almost exactly the way she fantasized about doing to earn his affection earlier), and when he tries to apologize for how he treated her and offers to start dating her again, cave-Buffy hits him on the head with a stick.
Buffy: "Parker BAD"
Practically every lawyer show will use this trope as one side (knowing something the other side does not know) makes a transparently bad settlement/plea-bargaining offer to the other side, sometimes even saying "Decide quickly, because we're only offering this until I walk out that door," and usually followed after the refusal by "See you in court."
In Dragon's Den, one of the investors will sometimes retract an offer if the presenter waffles too much for a better deal.
A TV movie adaptation of The Lost World (by Arthur Conan Doyle) had the hero snubbed by a girl he liked at the beginning of the movie, only to have her try to chat him up after he comes back from the titular country with a pterosaur and lots of fame. He blows her off.
An episode of Rome had Mark Antony offer the recently-retired Vorenus a position as First Spear Evocati with a huge signing bonus. Vorenus turns him down, preferring to live as a merchant. When his stock of slaves suddenly dies, leaving him with nothing, he returns to Antony to ask for the position, and Antony eventually gives it, but reduces the bonus from 10,000 sestertii to 9,000.
The West Wing: After weeks of negotiations, the President and the Speaker of the House cut a deal to avoid a government shutdown by slashing government spending a certain amount. At the final meeting to sign the deal, the Speaker, perceiving President Bartlet to be in a weak position, suddenly demands sharper cuts. Bartlet balks and the government is shut down.
At the end of the same episode, Bartlet tries to resolve the situation by walking to Capitol Hill to negotiate another compromise solution (earning large amounts of positive press along the way). When the Speaker and his allies respond by keeping Bartlet waiting as they try to decide on their demands he simply walks away, leaving the Speaker painted as the one responsible for the continuing shutdown.
Happens on House when a detective offers a deal for House to go to rehab in exchange for temporarily giving up his licence. When a depressed House shows up (on the last day of the deadline) finally beaten into accepting it, the cop says it's off the table.
In Boardwalk Empire, after Eli betrays his brother Nucky to join the Commodore's conspiracy and makes a phone call to taunt him about it, Nucky offers him one last chance to walk away from it; Eli blows him off, but after the Commodore has a stroke, loses faith in the conspiracy and begs Nucky to let him accept the offer. Eventually averted; even though Nucky tells him "That offer's gone" and then slaps him around, Eli is the only member of the conspiracy left alive by the end of the season, and he and Nucky have repaired their relationship to some extent.
Avril Lavigne's song "Sk8er Boi" is about a boy who has an unreciprocated crush on a girl. Then he becomes a rock star and she gets a crush on him, but he's no longer interested in her because he's in a relationship with another girl who liked him before he got famous.
Older Than Feudalism: In Roman legend, the Cumaean sybil visited Tarquin the Elder (the last king of Ancient Rome, 6th century BCE) and offered him nine books of prophecy for a great price. He refused; she burned three of them and offered the rest at the same price. After repeating this, he finally paid the original price for the remaining three.
One of the messages of Christianity as well as according to various scriptures of The New Testament such as John 3:36 and Romans 2:5 say that if a person dies while still rejecting God's gift of salvation, they can't change their mind in the afterlife to receive eternal paradise in heaven.
In William Shakespeare's The Merchant of Venice, the merchant Antonio defaults on a loan to the moneylender Shylock, and Shylock demands the promised collateral — a pound of Antonio's flesh. Antonio's friends come up with twice the amount of the original loan, offering it to Shylock to forgo the pound of flesh, but Shylock refuses. When it is then pointed out to him that the agreement specified only a pound of flesh, and if he were to spill a single drop of Antonio's blood while extracting the flesh, he would be executed in accordance with the laws of Venice at the time, Shylock tries to accept the previous offer of the money, but that offer is now off the table, so the trope is played both ways.
A Guide Dang It moment in the first Space Quest involved this when selling your hoverbike. If taken, the first offer would leave you without a needed item later in the game. Said item would be offered the second time, but never again.
One early use was in a 1930s Popeye short "Beware of Barnacle Bill", which has Olive rejecting Popeye's marriage proposal, Popeye beating up Barnacle Bill (the person Olive was in love with), and then rejecting Olive's proposal out of spite.
Doug: One episode begins with Patty being turned down from the school baseball team for being a girl, ends with Patty turning down school coach's offer to let her join after he saw what she could do (or rather, could have done: Roger's game-winning catch for the school was all that prevented her from driving in Doug as the game-winning run for her team the Pulverizers).
The Powerpuff Girls has fun with it, and gave the trope its original name "Turning The Other Cheek": Buttercup tells Bubbles that they shouldn't be "turning the other cheek" on an offer from a league of superheroes, and that offer has a twist: They're not asking the PPG to join (as the PPG has been trying to do, and were rejected simply for being girls) as Bubbles expected (and she was planning on rejecting the offer of course), they're asking to join the PPG.
Also done in the episode with the flying squirrel: Blossom and Buttercup are initially pleased that Bubbles has talked the squirrel into rejoining, but are then flabbergasted to hear that Bubbles is willing to let the squirrel stay in the forest.
The Fairly Oddparents, "Love Struck!" features a romantic variant on it. Timmy has been pining for Trixie Tang for the longest time (since season 1's "A Wish Too Far!"). At the end of this story, Tang asks Timmy to be his Valentine, which is what he's always wanted. It looks as if Timmy will accept, but then he suddenly sees Tootie (who he learned earlier in the episode is who he's supposed to be with) crying over a photo of himself on a bench. He says he knows he'll be kicking himself for this, but he actually rejects Tang's offer and asks Tootie instead.
In The Simpsons, Flanders sells his possessions when he needs money in When Flanders Failed. Homer wants to buy Ned's new grill cheap; Ned is reluctant but eventually agrees. At this point, Homer says he will only pay that price now if Ned throws in several other items.
In the pilot of Clerks: The Animated Series, Leonardo Leonardo offers the clerks a very generous payment (including college scholarships) to sell the Quick-Stop minimarket. Randall immediately and vehemently refuses. Dante tries to accept the moment Randall stops talking but Leonardo states that the offer is no longer on the table.
Real Life example: The White Stripes made the Fell In Love With A Girl music video entirely out of Legos and stop-motion. Jack White consulted with the Lego company about having Lego figures of Meg and himself packaged with the release of the single. Lego refused, claiming they wouldn't cater to a market that wasn't children. When the video was a hit, Lego changed their minds, only for Jack to refuse.
Bill Cosby summed it up in this famous quote: "When you're poor, people won't give you five cents for a hot dog. When you're a millionaire, people will pay through the nose to have lunch with you."
George Westinghouse wrote a letter to Cornelius Vanderbilt, president of a major railroad company, detailing his new invention (the train automatic air-brake) and asking for investment. Vanderbilt returned his letter replying only with the words: "I have no time to waste on fools". Once another railroad adopted the brake to great success, Vanderbilt sent an offer to buy a good number of the new brakes from Westinghouse, only to get the reply: "I have no time to waste on fools".
This has been cited as the reason there wasn't both an Arab and a Jewish state established in what became Israel right at the start. The Jewish Agency accepted the plan (proposed by the UN), but the Arab parties didn't and tried to drive Jews out of the area, leading to war. After the Arabs lost, the Jews apparently weren't too keen on the idea of letting them have that half anyway.