resale flat neogoiation tips

4bhk flat ( landowner share flat ) in bangalore. quoted price 2.71 cr, broker said the land owner will get it down to 2.59 cr based on previous deal price that did not go through. apprarently the land owner wants the money for some construction purpose. As per rates going in that area, the price should be around 2.4 to 2.5 cr. How much can i negogiate to bring it down. Unoccupied flat and the apartment is 5 years old