I recall that no matter how you purchase your ticket, you are not assigned a Dolphin Swim time until you arrive at DC. I would recommend that you arrive as close to opening as possible to get an early dolphin swim time. We purchased our tickets through DC and we not assigned a swim time until we arrived in the morning. (It has been 3 years, but I believe that is how it worked. We are going next month, but not doing the dolphin swim.) If I recall correctly, the difference in UT issued tickets and DC issued tickets is how they may be handled in the event you need to reschedule. I'm not positive, but if it were me I'd check into that question. Sorry that I can't be more help. Have a great time at DC! We love it!