Queries on Agreement of Sale

Respected Sir, I am from Bangalore. I seek you valuable guidance before proceeding further with my current plan of purchase. I see that there is a Agreement of Sale made between the Builder and the Land owner's wife on one of the many Flats in this Apartment complex. Whereas all other Flats are distributed between the two (Builder and Land Owner) as per the document. Agreement of Sale contains information about the initial token amount paid for the flat and couple of other terms and conditions like, - To whom (purchaser / nominee's) and when the sale deed can be executed (after No Due Certificate and Discharge Deed from bank where the property was kept as mortgage by the builder, free from all encumbrances, Occupancy and Completion Certificate from BBMP ) It also contains how the land was legally made available for the Builder for constructions and how the rights have been shared among Builder / Land Owner for general share of Flats in that land. Queries: - This agreement was made on 2018, how long is it valid as i dont see validity date on the document ? - Do i need to get this agreement cancelled if i have to purchase it from either of the involved party as i could see this details in the EC ? - Bank informed that a MOU , Tri - Party agreement (Containing the transfer of rights to me signed by both the above parties) , Account statement for this flat obtained from Builder , NOC and deed detachment obtained from the Bank, along with the usual legal documents would be sufficient to sanction a loan. > So should / can i purchase this flat considering the above Agreement of Sale valid ? > Which mode of purchase would be safe A) Cancel existing agreement of Sale between Builder / Land owner or B) Opt for the tri-party agreement / MOU / NOC as informed by the Bank personal ? - If the Agreement of Sale has been cancelled how will it reflect on the EC ?