You have three options.
1. Leave your 2nd seating traditional booking in place and see if you can make a change to the first seating once you get on the ship.
2. Have yourself taken off the 2nd seating traditional and put on the waiting list for 1st seating.
3. Change to anytime dining and once on board, see if you can make a standing reservation for 2. I've read on the boards that the prime-time for anytime dining is between 6-8...so, you may have a better chance for a standing reservation before/after these hours.
Obviously, each option has it's pros/cons.
Hope these suggestions are helpful.
We've always eaten in the dining room, so I can't speak to the evening offerings at the buffet. But, I've always found the selections for breakfast or lunch fine.
Just have to remember cruise food fare is not equivalent to gormet cooking.
We sailed on the Coral and loved the ship. Enjoy!