Transfer of property sale agreement

I have made an agreement to sell my house to a person and taken an advance. The buyer is unable to purchase the property now. I am not in a position return the advance.  

I want to enter into an agreement for joint development agreement with with a relative of the agreement holder. He too is unable clear the advance immediately .He says he get a letter releasing me from  the agreement. I am getting one apartment out of 3 which is being constructed. I want to be this apartment to be free from the scope of the agreement. How is this to be done

Execute a fresh registered agreement with specific covenents qua supersession of earlier agreement and new terms.

I have an unregistered agreement I have received few lakhs as an advance

Dr J C Vashista has suggested fresh and registered agreement.

Another Presective: neither you, nor (unregistered) agreement holder, nor relative of (unregistered) agreement holder are presently in a capacity to perform the agreement.

The relative of (unregistered) agreement holder can not clear the advance immediately.

Why do you want to be with a party about whom you already know that he does not have the capacity?

Does he have capacity to raise the building?

You are closest to the facts.

Apply your own judgment!