Once you've made a reservation, you can change the resource that the reservation is for.
Go to the calendar of the initial resource and select the reservation you want to change. Select Edit, and from the Edit window you can choose another resource under the Resource field.
The reservation and all its details will move to the new resource that you select. Go to the calendar of the new resource to view the reservation. You can only move non-loanable reservations to non-loanable reservations.