A man may appoint an emissary to deliver his writ of divorce to his wife, and this is called a "messenger for delivery". It is not a valid divorce until it reaches her hand. Therefore he can back out until the writ reaches her hand.

All of the laws that apply to a husband with his wife, with respect to giving the writ of divorce and reading it and speaking about it, also apply to his emissary's conduct with her. Rem"a: The rabbi who organizes the transfer [of the writ] with two others with him (as explained futher on (Shulchan Arukh, Even HaEzer 142:4)) should review the writ first to ensure that it is written properly as explained later on in the process for writing the writ (Shulchan Arukh, Even HaEzer 91).

A woman appoints an emissary to receive [the get], and she is divorced when he receives [the get] immediately when the get reaches his hand. And the ruling for him is like the ruling for the woman in every way, for the matter of whether he threw the get to his courtyard or to within four amot of him. Hagah: And he writes in the get: Behold you are permitted etc., but when he gives the get he says to him: Receive this get for my wife (the Ran first chapter of Kiddushin).

If she said to the agent, "Accept for me my get," or "Take for me," or "It shall be for me in your hands," these are all [valid] language [to appoint an agent] for acceptance [of a get]. Rama: Some authorities also accept "Pick it up for me" (Beit Yosef in the name of Rashi and Magid Mishna) or "Take for me" (Ri; the first 'take for me' above was in Aramaic, the second was in Hebrew).

She may also delegate an agent to bring it to her, as she may say, "Bring me my bill divorce," and his laws are the same as those of an agent of the husband, that it is not considered a bill of divorce until it reaches her hands. Homessengerwever, the man is unable to accept it as her agent, for he may not be made an agent to perform her obligation without hmessengerer knowledge, even if she were the wife of one afflicted with boils, or there was strife between them and she requested a divorce. There is one who says that in such a case, her divorce is subject to doubt. Rem"a: If her husband is an apostate, and it is known that she is seeking a divorce, there are those who say that the apostate may grant her a bill of divorce (T"H #237 and in his decisions #43). There are those who are stringent even in this (Ra"n in a responsum). So too if the levirate husband (see Beit Yosef) was an apostate, the husband can grant her a bill of divorce so that she will not fall before a levirate marriage (see Beit Yosef). If his wife was an apostate, her bill of divorce may be acquired for her via another (see T"H #237 and in his decisions #44), as has been explained above, even though she went back on it afterward, she does not need another bill of divorce (T"H ibid.). This is also the case for a woman who has become forbidden to her husband--the bill of divorce is transferred to her via another person. There are those who are stringent in this (Mahari"k #141).

A woman who appointed an agent to receive the get, and the husband said to him: I don't want you to receive the get, rather this is her get and you should bring it to her, the husband has permission to do so, and he becomes an agent to bring her the get. But if he says to him: Receive this get for her, or here it is, or merit it for her, he has not uprooted the agency to receive the get. But if he says to her: Take it to her, he has uprooted the agency to receive the get and the agent has become the husband's agent. And also if he says to her: Bring it and give it to her, he has uprooted the agency to receive the get. And in both cases, she is not divorced until the get arrives in her hand. And there are those who say that if he says "give it to her" she is doubtfully divorced (Ran, ch. hitkabel in the name of 'there are those who say').

If she didn't appoint him as an agent to receive the get, and the husband says: Receive it for her, when the get reaches her hand, she is divorced. For one knows that he can't appoint an agent to receive the get, and he meant--take it and bring it to her.

If she appointed an agent to bring her get, and he came and said to the husband: Your wife appointed me as an agent to receive her get, and he (the husband) said: Take it like she said, even if the get arrives at her hand, she is not divorced. But if the husband said to him: Bring it to her, or acquire it for her and didn't say: like she said--when she receives the get, she is divorced.

If she made an agent to receive the get, and he came to the husband and said: Your wife made me an agent to bring the get, and he said: Bring it to her, like she said, once the get arrives at her hand, she is divorced. And if the get is burned or lost before it arrives at her hand, she is doubtfully divorced.

If she appointed an agent to receive the get, and he came to the husband and said: Your wife made me an agent to bring the get, and the husband said to him: Accept it, and he didn't say: like she said--once the get arrives at her hand, she is divorced. Hagah: If she made him an agent to receive the get, and the agent said so to the husband, and the husband gave the agent a document to bring and then he gave him a document to accept, if he gave him the get when he gave him the document to bring, behold he has annulled the agency of his wife. And then when he went back and gave him to receive it, behold he has annulled the agency to bring it. And a husband cannot appoint an agent to receive the get and therefore there is no agency at at all. And she is not divorced through this agent. Rather he should go go back and he should give it to him for the sake of the agency that the woman created. But if he gave him the get only when he gave him the document of agency for accepting, she is divorced immediately when he gives him the get, for since he didn't give him the get at the outset, the agency appointed by the woman has not been annulled. (Bet Yose in the name of the Ribash, siman 329).

If her hand was katafres (explanation - she had her hand slanted [ obviously ready to receive the divorce bill], and not vertical like a partition not ready to receive), and he threw the divorce bill towards her hand and it fell on the ground: if it fell within four cubits and it stayed there, this is a divorcee. And if it did not stay within [the four cubits], and rather rolled immediately outside of [these boundaries], this is a doubtfully divorcee. If [the divorce bill] fell into the sea or into the fire, she is not a divorcee. And if it was close to the water or the fire - from the beginning of the fall it was in position to be destroyed. "Rem"a:"