To switch account in Clash Royale app on BlueStacks, please follow the steps mentioned below:
1. Click on 'Settings' icon on Clash Royale.
2. Tap on 'Connected' option as shown below.
3. Once your current account is disconnected, click on 'disconnected' option. Here an option will be displayed with all the account that are added on BlueStacks.
4. If no other account is added, you can 'Add an account' as shown below or use this url to add an account http://support.bluestacks.com/hc/en-us/articles/206505806
Now you can switch between existing accounts.
If you are facing any difficulty, write back to us at firstname.lastname@example.org.
Syncing Clash of clans village with your account switching accounts in Clans of clans