All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His Slave and Messenger.
The stated gifted money has become owned by the recipient; for he left it as a trust with the agent until he meets him. Al-Qaraafi said in his book Ath-Thakheerah: "If the recipient (of Zakah) knew the matter and said (to the agent) keep it with you, then it is his own money; for it was received by the agent and made a trust with him."
Accordingly, it is no longer owned by the giver and he does not have to pay Zakah on it.
Allaah Knows best.