Call of Duty Mobile lets you connect your Facebook account for save data, but you may find that you want to change your Facebook account.
This is possible to do. However, the process is rather convoluted. There are multiple steps. And, it's nowhere near as easy as connecting to an account.
This step by step guide will help if you want to change the Facebook account your Call of Duty Mobile account is connected to.
To change your Facebook account, start in Facebook
To change your Facebook account in Call of Duty Mobile you first have to start in Facebook. You can do this either in the app or on the web. It doesn't matter.
The first thing you will want to do here is go to the settings page where "settings and privacy" is listed. In the Facebook app, this is located by tapping the three lines button. Which is located at the far right of your navigation tab at the top. (On the web, you can find settings by clicking the drop down arrow button in the top, right-most corner.)
From here, settings & privacy is all the way at the bottom. You should see it just above the log out option. Tapping that will expand this section, where you can find settings. Tap this menu.
Find the Apps & Websites option
Once inside settings you will see a menu called Apps & Websites. This menu shows all of the apps and games that are linked to your Facebook account.
Inside of this menu is another menu labeled as Apps, Websites and Games, and this is where you will need to go next. You will find this menu just under Logged in with Facebook. It's also listed under the "preferences" tag.
Tap on this menu to find every single game or app that Facebook is connected to on your behalf.
Select Call of Duty Mobile and tap remove
Depending on how many things you have connected to your Facebook account, Call of Duty Mobile should be relatively easy to find.
Scroll through the list of apps, websites, and games, and tap Call of Duty Mobile to select it. After it's selected you should see a little blue check mark next to its icon.
Once you see that's there, tap the remove option. This will be towards the top of the screen, where the word remove will be inside of a blue button. This will completely remove Call of Duty Mobile from your Facebook account.
Confirm you want to remove your account, & delete any related data
Next, you will need to confirm you want to remove Call of Duty Mobile from your Facebook account.
If you wish, there is also an option here to delete any related data. More specifically, this will delete any posts, photos, or videos on Facebook made by Call of Duty Mobile.
To have this done, tap the check box above the remove button. After that, tap the blue remove button. It should only take a moment to complete this particular step. Afterwards Facebook will no longer be connected to Call of Duty Mobile.
Log out of Facebook
After you've removed Call of Duty Mobile from your Facebook account, you will need to log out of Facebook.
You will need to do this in both the Facebook app, as well as Facebook in a browser. For the browser portion, you can log out of Facebook either in a mobile browser, or on desktop. Both will work.
After you log out of your Facebook account in both the app and on the web, you're just about done with this whole process.
Change your Facebook account in Call of Duty Mobile
This is it. You're at the end of the entire process to change your account. The last thing you will actually need to do is log back in within the game.
Open up Call of Duty Mobile, and when prompted to login, select the Facebook option. You will now be given the choice to select which Facebook account you want to login with.
Something to keep in mind is that this will really only be useful if you have more than one Facebook account. That being said, you're finished, and you can now go back to playing. You can use this process to switch between Facebook accounts at any time.
However, any data you have on one Call of Duty Mobile account will be stuck with that first Facebook account. It will not transfer between Facebook accounts. Currently, there still seems to be no way to unlink any progress from your Call of Duty Mobile account from the Facebook account you first selected.