Modify reservation bought with rapid rewards point...

Hello, I purchased a flight from Milwaukee to Las Vegas using my Rapid Rewards points. I had just purchased a ticket for my wife for the same flight minutes before with a credit card since she didn't have enough points to use. Unfortunately, the price increased between purchasing her ticket and purchasing my ticket. I went ahead and purchased the ticket anyway. I'm hoping the price will come back down. If it does, what is the best way for me to get the lower price using my points. Do I cancel my reservation? And if so, how long will it take for the points to go back into my account since I don't currently have enough points to use? Or do I modify my reservation/change flight and rebook the same flight at a lower fee/points? If the flight costs fewer points than when I first booked it, and I change my flight, does the difference in points go back into my account? I also used early bird check-in with my reservation. How would I go about making a change to my reservation to get the lower fee/points and still have the early bird checkin? Thanks in advance.