How to handle candidates applying to wrong requisition

Content

My client has a scenario in which a candidate applies to the wrong requisition. When asked how they can move them to the correct requisition, I explained how to add them to the new req and create an application on their behalf. Then I explained to mark the original application on the wrong req as withdrawn by candidate or rejected by employer (with appropriate reason).

This solution is undesirable by the client. They would like some way to simply port the application to the correct req so only one application exists in the system and there is no need to withdraw/regret.