[Koha] How to reverse the wrong Item Entry

[Raphael Muonga]

My colleagues I need help to a write some SQL code to reverse the
"ordered" entry in the "Not for Loan" field for the books which were
erroneously entered like that instead of leaving that field blank in
the first place so that they can be illegible for loan. The records
are too many to be edited manually!

Thanking you in anticipation.

Raphael Muonga