1,756. Canceling a Get
Hilchos Geirushin 6:15
If an agent acts counter to the law and gives a woman her get in private, he should take it back and give it to her again in front of witnesses. If the agent who delivered the get in private died but the signatures of the witnesses on the get in the woman’s possession have been confirmed, then the divorce is valid.
Hilchos Geirushin 6:16
Even after a get has been sent to the woman, it can be canceled as follows: Let’s say that the agent took the get but the man sending it changed his mind before it reaches his wife. He can tell the agent or the woman that the get he sent her is void, he can send another agent to cancel the get, or he can tell others that the get he sent his wife is canceled. When canceling a get in front of others, there must be at least two present. If the get has already been delivered to the woman or to her receiving agent, her husband can no longer retract it. This is so even if he cancels the get immediately; since it was canceled after reaching the woman, her agent or her courtyard, it is not canceled and divorce is effected.