1. If there are two applicants for taking loan from the bank, the loan will be for purchasing some property, ordinarily housing property.
2. So, while availing the loan in joint names, you have submitted copy of agreement for sale executed by the builder/vendor with both of you being the co-applicants.
3. So, the bank has nothing to say in whose name the property will be registered after they get their loan amount repaid by you alone or jointly with the other co-applicant.
4. You shall have to negotiate with the co-applicant for availing a letter from him to the Vendor withdrawing himself as the co-purchaser of the said property wherein you shall be the sole owner of the same.
5. After getting a letter confirming your sole ownership by the vendor (for which he might insist for a fresh agreement wherein the co-purchaser will be a consenting party), you can write to the bank that you shall be the sole purchaser of the said property for which you should be treated as the sole borrower of the loaned amount to be rep[aid by you.