What is the ruling on selling housing units granted under the rent-to-own system before acquiring ownership, and is the seller entitled to demand a price increase upon final subscription?

In an Ijara-wa-Iqtina (lease-to-own) contract, the lessee does not own the property during the leasing phase, and their sale of the property is invalid. If the seller is the lessee and the buyer is purchasing from them during the lease contract, the sale is void. However, if the seller is the lessor, they may demand any price agreed upon by both parties. If they have agreed to sell the property at market price or to gift it, then the lessor is obligated to fulfill this promise. If the lessee wishes to own the property before the end of the lease term, the price shall be by mutual agreement between them and the owner.