How do I change the default FaceBook account used in ios 15.3.1?

BitRatBill wrote:

I have the FaceBook app installed on my iPhone and use it with my correct FaceBook account. However, if I try to login to another app using FaceBook integration, my phone tries to use an old account. How can I clear that or swap it?

I have looked under Settings/Facebook and there is no option.

I have deleted and reinstalled the Facebook account, loggin into the correct new account.

Neither worked.

Contact facebook or look at their help center.