Yes, you can change the date of your booking directly from your confirmation email: click the “Change my reservation date” button. The change is possible if your booking conditions allow it and depends on the hotel's availability. A prepaid, non-modifiable booking cannot be moved to another date.
The hotel, however, cannot be changed: you need to cancel the original booking (if it is eligible for free cancellation) and make a new booking at the hotel of your choice.