Is it permissible to dissolve a partnership for a piece of land that was purchased in installments, and to return the amount paid to the partner, knowing that the land is registered in the name of one of the two partners?

If the sister who is asking bought a piece of land from a savings fund, and then permitted her sister to share in the land provided she pays half the price, this means that she sold her half of the land she owns for a known price to be paid in installments to the savings fund. This sale is valid and binding, and the sister who is asking does not have the right to revoke it, for the Prophet, peace and blessings be upon him, said: "The two parties to a transaction have the option [to annul it] as long as they have not parted." Therefore, it is not permissible for the seller to annul the sale once it has been completed and met its conditions, except with the buyer's consent.