%%See this [[http://tvtropes.org/pmwiki/posts.php?discussion=1326204594031000100&page=1#18 thread]] for the reason why the picture was moved.
->'''Nurse Mary:''' Tell me, Captain Blackadder...\\
'''Cpt. Blackadder:''' Edmund.\\
'''Nurse Mary:''' ''(grins)'' Edmund.
-->-- ''Series/{{Blackadder}} Goes Forth'', less than a minute before the RelationshipUpgrade.

The sudden switch in nickname or [[{{Honorifics}} honorific]] when referring to a character, usually from their family name to their given name, is frequently used to demonstrate a [[RelationshipUpgrade significant change]] in the relationship between two characters, the desire for one by one party, that they have evaded listeners who require more formality, or that they are [[NotHimself Not Themselves]]. Never using ''any'' formal indicators and just calling a character by their exact name is about as common to show the same thing.

Another common trope is a character saying the other's actual name rather than some [[HeyYou rude variant of "you"]] or [[AccidentalMisnaming of their name]] to show a relationship getting closer. The other situation is a character who was previously irritated to be called by a "cutesy" name finally accepting the moniker, usually from the sort of overly cheerful character who [[TheNicknamer does that with everyone's name]].

Propriety may demand that it be used only in private. Referring to a character by a first name to a third-party can reveal the nature of the relationship. This can range from a total accident to an intentional flaunting.

Juniors may stubbornly insist [[TheyCallMeMisterTibbs on titles and family names]] when they think the senior is using his authority to feign friendship.

For the creepy use of this by an enemy, see TermsOfEndangerment.

Keep in mind that in Japanese the family name comes first so in anime and manga this is more of a "last name basis"[[labelnote:*]]In Japanese the given name is called "shita no namae" or "bottom name", referring to the vertical writing[[/labelnote]]. Wiki/ThatOtherWiki almost always reverses this order for westerners, as do some translations (and many Japanese themselves when they write names in alphabet), complicating things considerably. Bonus points are awarded if you notice in the audio that one name is used but in the subtitle a different name is used. Note that this is much less important in languages other than Japanese, because most languages just automatically use First Name Basis to denote equality and/or friendship, more or less. Except when they don't.

A variant of this is when a character on first name basis is known and called exclusively by the diminutive version of that first name. Therefore, a character, named William, regardless of the situation, is "Will", "Bill" or "Billy". The character uses his full first name only when he is required to (official paperwork and I.D., for example). This can occur in unusual circumstances where it's not expected, such as Jimmy Carter, Bill Clinton, and Prince Harry for example. This is often a deliberate, individual preference in the interest of a promoting a more unassuming, less high-falutin' persona.

This trope is the polar opposite of TheyCallMeMisterTibbs. Compare LastNameBasis, when the characters never made the switch, FullNameBasis if they never even switch to last name, and HeyYou. May get interesting when the character is PalsWithJesus.

[[IThoughtItMeant Not to be confused]] with OneNameOnly, such as Prince, or Cher.

* FirstNameBasis/AnimeAndManga
* FirstNameBasis/ComicBooks
* FirstNameBasis/FanFiction
* FirstNameBasis/{{Film}}
* FirstNameBasis/{{Literature}}
* FirstNameBasis/LiveActionTV
* FirstNameBasis/VideoGame
* FirstNameBasis/WebComics
* FirstNameBasis/WesternAnimation
* FirstNameBasis/RealLife