Invoice changes resulting in a "Needs Revalidation" status?

Hi all,

Recently we've had an issue where a staff member went into a batch previously validated by another staff person, making a change to each invoice which resulted in a "Needs Revalidaton" status on each invoice.

No one recalls the exact change made, which has led to the question: is there some type of listing of changes which will cause a validated invoice to need revalidation? Intitial searches on MOS haven't turned anything up, so I'm hoping someone in the community knows of such a document.

Thanks!

Vanessa