Is it permissible for a sister to retract her waiver of her share in the shop to her brother after the death of their parents?

What the sister relinquished should be returned to preserve affection and uphold kinship ties, and to reciprocate kindness with kindness, for the Messenger of Allah, peace and blessings be upon him, said: "Whoever cancels a Muslim's transaction, Allah will cancel his slip." It is also mentioned that returning what the sister donated is more appropriate when she regrets it, and she should not be compelled to ask for it so as not to put her in an awkward position. If her initial relinquishment was due to shyness, then it is not permissible to take that money, and it must be returned.