How to proceed with possible book error?

[MechanicGuy]

Originally Posted by APG

You have definite knowledge that he has four fouls, you tell the official scorer to correct the error. If you don't have definite knowledge, you go with the official scorer.

If the scorer doesn't want to do that, either have the scorer replaced or make the visiting book the official book.

I agree with this.

But, how do you simply add a foul to his count? What if they mistakenly marked a foul of his on a teammate? If it happens in the second half, how do you know when the foul was missed?