Open Clash Royale on your Android device
Tap the gear icon to open Settings
Tap Supercell ID
Tap Log Out
Confirm the logout
Clear the Clash Royale app data in Android Settings
Open Android Settings
Tap Apps
Tap Clash Royale
Tap Storage
Tap Clear Data
Open Clash Royale again
Follow the setup prompts
Choose a different Supercell ID or create a new one
Sign in with the new account
If needed, install a fresh copy of the game after removing app data
If you want to keep multiple accounts, use separate Supercell IDs for each one