No, that is not possible. Submission of an offer is binding. As the total auction mechanism is very complex and each offer is considered, the withdrawal of a single offer would falsify the total auction. Add to this the fact that the borrower expects the promises made to be honored, and would have to face a big delay in receiving his payment otherwise. After the submission of his offer, each lender is therefore asked by the system specifically whether he gives his consent to the binding offer.