Basic Trope: The character who received a promise releases the promise-maker.
King Arnold got Sir Benedict to promise to guard him. When he solidifies his position on the throne and got more guards, and Sir Benedict has fallen in love with a lady, the king releases him from his promise so he can marry and help protect her lands.
Sir David promised to retrieve a stolen item for Lady Catherine; when she realizes the danger, she releases him.
Edgar promised to work for Frederick on the condition that his payment be a valuable piece of art. When the art is stolen, Frederick tells him he is free to go.
Georgiana, realizing that they are facing a Last Stand against the Evil Overlord, tells her sworn guards that they do not need to defend her, she will surrender.
Hendrick, knowing the danger of going into the swamp, frees his men from their oath to follow him anywhere; they angrily declare their word is not that cheap, demand to share his dangers, and point out that they would be regarded as oathbreakers because they have only their word that he freed them.
Downplayed: Jacinth tells Karen that her promise to bring her a book doesn't mean she has to do it immediately.
Amy realizes that freeing Bernard from prison on the condition that he promise to serve her was unjust, because she realizes he was innocent. Feeling petty and less than him, she frees him on that grounds.
Carolus realizes that Davida promised to marry him only to escape her family, and frees her.
Inverted: Zaffire realizes that Esmeralda's old promise to help her is the only way she can escape from her father's enemies, and goes to demand she live up to her promise.
Annabella says it would be nice of her to free her guards from their oath after their selfless defense of her from an attack, but she doesn't think she'll do it.
Bonita tells her sworn guard Constantine that he is free of his oath, and he fiercely refuses: she can not undermine his word.
King Arnold needs Sir Benedict as a spy and publicly releases him from his original oath and then takes a new one.
King Rufus tells his captive Prince Stephan that he will free him of his oath to remain a prisoner — on the condition that he marry Princess Thomasina and remain forever in court. The prince refuses it.
Double Subverted: Though she can reassign them to far more pleasant tasks, despite their oath to act as bodyguards.
Parodied: King Andrew makes Lady Berniece swear to tell him the truth. She begins to tell him the truth, the whole truth and nothing but the truth all the time, including how stupid he looks rising in the morning, and he frees her from it.
Zig Zagged: ???
Averted: No oaths. Or any oaths are fulfilled or broken before the question arises.
Invoked: Ferdinand acts obnoxiously toward his mistress Lady Odette, hoping she would free him from his oath to serve her.
Defied: "No, my liege. I am grateful that you think enough of me to consider it, but I Gave My Word."
Deconstructed: Zulieka frees Yvonne and Winifred from their oath to her with such melodrama and emotional blackmail that they feel even more bound to help her.