So my family and I are planning a trip for Halloween 2021 for my daughter's birthday. We'll be staying with my parents at their DVC room. On Disney's site, park passes are only available until September 26, 2021. My Disney Rewards card has a 5x rewards promo that ends at midnight tonight. Is it possible to purchase tickets with a September date and adjust the dates in a month or two when the dates we're going are available? Or do I miss the 5x rewards promo and wait?