Android project, change Firebase Account

1- Yes, it's possible and you can follow this tutorial to do so.

2- If you want to simply switch projects, generate a new JSON on the console and remove the old one. If you want to migrate your database, it's possible, just check this question.

3- Both answers are "yes" so, try them out.

Follow the below steps, to switch firebase account

1. Go to your firebase console, and select the project you want to shift

2. Select the icon besides the project name on top right.

3. Select Permissions from the flyout.

4. You've reached the IAM & Admin page of firebase.

5. Click on +Add button on top.

6. Enter the email ID of the account to transfer the project to.

7. In the dropdown, Select a role > Project > Owner. Click add Check mail in the email added above.

8. Accept the invite, and go to IAM & Admin page of the transferred project.

9. Use remove button to delete the previous user

Hope this helps.