If you want to change the main user of your account, please perform the following steps:
- Tap the Profile button (the last icon on the bottom bar of the app)
- Scroll down, and tap 'Log out' — then log back in.
- When you are prompted to select your profile, tap the name of the user you want as the main user.
The user you've selected is now displayed first in the menu. Note that only the main user has a Timeline, a Leaderboard and the ability to set reminders.
