If you are a dual member with two (or more!) quartets, first understand that Sweet Adelines only gives directors any preference when scheduling the order of appearance. Your two on-stage times could be hours apart...or they could be back to back!
So... several things can be thought through NOW to make handling all of this easier before contest is in full swing. Reading and understanding these points will make your day less stressful!
We have changing rooms backstage for singers needing to make fast changes when one performer quickly follows the other. Singers will have to leave the backstage area if they are not immediately joining the next performer.
For those who have several performers in between, you may have time to go back to your room, change, and join your second group somewhere along the traffic pattern! Or if you don't have quite that much time, feel free to change costumes in one of the restrooms in the convention center.
Tips to make things go smoothly:
1) Bring ALL of your second (and third?) costume parts in their own shopping or garment bag(s) to the stage area before the briefing on Thursday afternoon, or before the quartet contest on Friday. Have all of your clothes bags clearly marked with your name and quartet, and leave it in the dual member changing room. There'll be a coat rack to hang costumes on and floor space to put bags.
2) Make sure you know exactly what costume is being worn for contest day; is anything suitable for both? Can you wear the same velvet pants? The same makeup, but with new lipstick?
3) There are approximately four minutes between quartets. Practice making quick costume changes and figure out how to avoid messing up a hairdo!
Good luck!