Yes. To start another wedding project, please log out from the bottom of the More tab.
Tap "Start a Wedding" and begin creating the next wedding project. During the setup process for the second project, when you get to the screen where you are asked to create an account, there is a link at the bottom of that screen to log in. Tap that and then log into your account. Your second wedding project will now be associated to your account.
If you need to switch between wedding projects, go to the More tab and tap the "Switch weddings" row to set your active project. Only one wedding is loaded on your phone at a time so as to save space on your phone.
If/when you need to switch projects, we recommend being connected to wifi so it switches the fastest.