Originally Posted by channa

If the availability is still there, redeposit the award, transfer the miles, and book with UA, then create the waitlist.

Note that when CO redeposits, sometimes the miles come back immediately, sometimes they take a few days (or you have to get the OPSC involved to do it immediately). If you do not have spare miles, you may want to try this during business hours so that they can contact the OPSC to do the redeposit in case the miles don't post back immediately.