A change cup is a price that must be returned
A bill of exchange (also called Bill of Exchange Jar) is a prize you won, but which you also have to return. Often there is a price (in cash or kind) that can be retained in this delivery price. In sports competitions there is often a change cup. Remember the UEFA Cup, the winning club may leave the Cup in the prize box until the next final, then it must be returned.
Pictures of alternating cups