I'm a newb to UA - my apologies. Just got my first set of CRUs and looking into using it for myself and the spouse BOS-IAD-DEN (3 cabin IAD-DEN). I'm a touch reluctant to use it as this routing would be eligible for UDU - but the upgrade space on IAD-DEN is currently available and I could clear the CRU now.

Have any members had any success clearing CRU and then 'downgrading' near UDU window if availability looks good to try to get a freebie UDU? Just writing it sounds sketch but if there are no rules against might as well try to preserve 2 CRUs.