If you have already participated in a current Team War, you can leave the team, come back to it, and still be eligible for the remaining part of Team War. Anything you do for the Team War is considered participation (voted on at least one card, spent at least one Bottle Cap, and so on). However, once you have participated for any Team, you will not be eligible for Team Wars for any other teams. If you have not participated in a Team War and switch your team during the Voting Days, you will be eligible for your new Team's war. If you plan on changing a team, Voting Days is the only time you can do so without missing out on a Team War.