What is the ruling when a creditor demands payment, and the debtor claims to have transferred the debt obligation (Hala/Huwala) to an absent third party, and the original creditor denies this transfer?

Primary text

If a debtor claims a transfer of debt obligation (Huwala) to an absent party and the creditor denies it, the statement of the creditor stands provided he takes an oath. However, if the debtor possesses clear evidence supporting his claim of the transfer, this evidence must be heard in order to discharge the right of the party to whom the debt was allegedly transferred.