Rectification of sale deed

Hello friends

I have purchased a re-sale flat (under construction) recently. The original deed between the vendor and builder was in 2008 and the new one between me and the vendor was in feb 2010.

In December 2010 the builder decided to change the name of the building (added "luxuria" to the old name) and informed the bank etc about the name change.  My seller and myself unaware of this change , went ahead and made the new deed with the old name. Builder had also informed the financial instituntions about the name change officially.

Now when I approached a bank for  housing loan , they are requesting for a supplementary agreement (tri-party agreement) between builder , me and the vendor regarding the name change. 

But what builder and other SMEs say is that, as the builder had already informed the bank officially about the name change, a tri-party agreement is not required;but a deed correction document between me and the vendor with a copy of the builder's official letter (mentioning the name chage) enclosed in the deed correction document is sufficient. 

Builder has already given me a letter on his letter head regarding the name change.

Now can you pls help me whether I would need a tri-party agreement or just a deed correction between me and my vendor.

Thanks in advance.

Regards

Prem