Help pls - Content date search then reformat date for rename

This screen grab illustrates what I'm trying to do.

After finding the date within the PDF document, I'd like to reformat the date before renaming the file:
YYYY_MM_DD_OriginalFileName_Extension
(the end result should look like: 2015_12_01_MyFile.pdf )
So that it is alphanumerically sortable in a folder.
All ideas appreciated!!!

After finding the date within the PDF document, I'd like to reformat the date before renaming the file:
YYYY_MM_DD_OriginalFileName_Extension
(the end result should look like: 2015_12_01_MyFile.pdf )
So that it is alphanumerically sortable in a folder.
All ideas appreciated!!!
