Help with ReValue Tool

How would one use the ReValue tool to renumber sheets that have a mix of “patterns”? A project I was asked to help fix has some sheets that are numbered A701 and others that are numbered A701.1 for example. I’m needing all of the selected sheets to increment up from A701.

So if the list is:
A701
A701.1
A701.2
A702
A703
A703.1
and so on… I’m wanting these to be renumbered A701, A702, A703, etc.

I haven’t found much documentation on how to use the ReValue tool and especially not for this mixed pattern scenario. That, and regular expressions are… strange. Any help would be greatly appreciated.