Note that if you have the points in your account and make the reservation now, the online system will automatically pull the points and order the award. When the e-cert is deposited, you shouldn't have any trouble calling MR and asking them to change the one-night reservation to the e-cert and redepositing the points.

If you don't want the points pulled from your account, then you will need to call MR and ask them to make the reservation, but not pull the points. Just don't forget to link the e-cert to your reservation once it is deposited. Otherwise, the online system will automatically pull the points and order you the needed award about 7 days before the check-in date.