In the Pages panel you can drag the required Master page over on top of the pages you want you want changing back.
That's not really going to do it. Instead it will leave you with both an overridden copy and a non-overridden copy behind it.
Better is to go into the Pages panel flyout menu and choose Master Pages > Remove all local overrides. This command works page-by page, but it might be scriptable to do an entire document at once.
I think I may have misunderstood the question.
Peter, thank you, this will work although it is still a long-hand solution (I have a handful of documents with 40-50 pages.) I will work on this though unless anyone else has figured out a script that would apply to the whole document.
In Applescript it's (be careful this will remove any content added after the overrides):
tell application "Adobe InDesign CC 2014"
set api to all page items of active document
repeat with x in api
if overridden master page item of x is not nothing then
remove override of x