I have emigrated, but can I resell the house at the homestead or give it to others?

Regrettably, according to the existing situation, if the house has been registered, the gift contract has come into effect and has been executed, and the house cannot be returned.

Unless there is an obligation clause in the contract, if the granddaughter fails to fulfill the obligation clause, she can claim to terminate the contract.

It depends on the content of the agreement. If there is no written agreement, it will be very troublesome.

Look at your supplementary explanation:

First, the old man is a person with full capacity for civil conduct, and the gift of disposing of his own property does not need to be confirmed by other children.

Second, for the party who is completely donated, it does not need capacity, and even the incapacitated person below 10 can accept the gift.

Third, if the house has been transferred, it is no longer the property of the elderly. Even if the old man is gone, it will not be regarded as his legacy. There is no harm to the inheritance interests of the donor's other children when the husband and wife divorce.