Official Book Change

[The R]

Middle School game last week.

At half time the visiting team book keeper brings to my attention that there is not a #31 in the book but #31 checked in and played.

I check the official book and there is a line crossed through #10 and a #31 written beside it. The clock keeper (the only adult at the table) says oh yea I forgot to tell them we changed the number before the game began.

Visiting team score keeper replies yea but you are the one who wrote your names/numbers in my book.

So we don't know for sure when the correction was made.

How do you handle this?
What call do you make? If you have a no call what do you tell the visiting team?