1. Verify from the builder as to who is the applicant and who paid the 90% consideration. If there is going to be re-allotment,the builder is required to inform you his willingness for the said re-allotment and the terms for it. without the builder's written confirmation, you should not act in this regard,
2. Verify from the builder whether he has received any payment from any Bank directly or not. If yes, then it is obvious that he has taken loan from the Bank duly mortgaging the flat. However, you should take confirmation from the builder also that he has not given consent for any such mortgage and the said flat has not been mortgaged,
3. The builder shall have to confirm you that thre is no dues in the name of the said allottee,
4. If the builder is a small entrepreneur then he will agree for entering in to a tripartite agreement with you and the allottee. If he is a big one, then he my not agree to be a party to the agreement but will certainly agree to give you answers to all your queries in details after which you can enter in to an agreement with the allottee and submit it to the builder for re-allotment of theflat in your name.