Yes, though you will have to pay whatever fees are appropriate to cancel the award based on your elite status.

The only exception to the "no partial use" rule noted above is for a BF upgrade. If the BF segment doesn't clear but any non-BF segments do you get to keep the non-BF upgrades and you get your points plus co-pay back. So if you booked MCO-EWR-LHR and MCO-EWR cleared and EWR-LHR didn't you'd get that first upgrade for free.