In recent months, if you want to extend or shorten your reservation, Hyatt wants to reprice it at current rates. This often means a price increase. Sometimes the price increase is huge.

To circumvent the price increase:
- If you want to arrive earlier or depart later, keep your existing reservation and book a new reservation. Then call in to combine them (or just do it at the hotel when you check in).
- If you want to depart earlier, just check out early. Most hotels post the charges daily, and very few (if any) Hyatts have early departure fees.
- If you want to arrive later, then you'll just have to book a new reservation at current prices.

To the OP's original question, if you're unsure of the travel dates, booking separate one-night award reservations is definitely the way to go. When plans firm up, you can keep what you need (and even combined them into one reservation) and cancel the rest.