When young children form a joint commitment with a partner, they understand that this agreement generates obligations. In this study, we investigated whether young children understand that joint commitments, and their associated obligations, may likewise be dissolved by agreement. The participants (3- and 5-year-olds; N = 144) formed a joint commitment with a puppet to play a collaborative game. In one condition, the puppet asked permission to break off and the children agreed; in a second condition, the puppet notified the children of his or her leaving; and in a third condition, the puppet just left abruptly. Children at both ages protested more and waited longer for the puppet's return (and said that the puppet deserved scolding and no prize at the end) when the puppet left abruptly than in the other two conditions (with "asking permission" leading to the least protest of all). Overall, 3-year-olds protested more, and waited longer for the partner's return, than 5-year-olds. Preschool children understand that the obligations of a joint commitment may be dissolved by agreement or, to a lesser degree, by notification.