The condition is only stated at the time of entering the state of ihram

Question: Can a person in the state of ihram who forgot to say after the talbiyah: (If something prevents me, then my place of ending the state of ihram is where I am prevented) say it after a period of time has passed since entering the state of ihram?

Answer: He cannot do that; it is only said at the time of entering the state of ihram. By entering the state of ihram, it is meant that one intends to enter it with his heart.