Possibility of changing a will

Hello.

A divorced woman owns an apartment, and the one who manages its rental and maintenance is her brother. In the rental contract, the brother writes, as the landlord, the name of their mother. In return for handling the apartment, he asks that his sister, the owner of the apartment, write a will bequeathing the apartment to his children. She does not want to bequeath it to his children, but rather to the children of her other brother. The brother who rents it out is a domineering person (gavra alima), and she is afraid to tell him that she does not want him to manage the apartment for her, and she also does not want to cause quarrels in the family. May she write a will in favor of his children, and afterwards a later will in favor of the children of the other brother?

Shalom u-verakha.

In the first will, she must leave open the possibility to retract it.

In siman 281, se’if 7 it is explained that a healthy person cannot bequeath using the formula of “inheritance,” but only using the formula of a “gift,” meaning that he can give a gift during his lifetime to whomever he wishes. Therefore, if he has already given his assets as a gift, he cannot give them again to someone else, and thus it is necessary to stipulate in the first will, which is essentially a gift, that he can retract the gift.