This is pushing Find/Replace.
How do you represent this music, specifically chords in Word? Word is a very unnatural way of recording music notation. Unless you know something I don't (which would not be a surprise to me ... <grin> )
If you already know of a way to do this change for a single cord, how do you do it. Is the find/replace example exactly how you currently would do one of these replacements? (Are those are exactly the find/replace criteria you already use?)
I don't have a complete answer to your question, but maybe you can piece together something from these clues.
This tip describes how to get user inputs in to a macro (if find/replace criteria)
Getting User Input in a Dialog Box
http://word.tips.net/Pages/T001356_Getting_User_Input_in_a_Dialog_Box.html
Find & Replace has Multiple Search Options
Word's Find/Replace uses two entirely separate search engines: simple text find and wildcard find.
The more familiar engine is adequate for very specific or very general targets ("Massachusetts" or "*"), but the lesser known engine is much more powerful, and
can track down and modify subtler targets such as any date, any time, or any dollar value.
To toggle between the two, check or uncheck Pattern Match.
For documentation, read the help-file page entitled "Examples of search wildcards" (in the Word97 help file search index, look for "Searching", choose the subtopic "Wildcards", and then click the "How" button under bullet 4).
For key differences between the two Find engines, see http://support.microsoft.com/support/kb/articles/Q176/7/76.asp
Word's Find/Replace uses two entirely separate search engines: simple text find and wildcard find.
Take a look at the tool mentioned in this tip:
Saving Find and Replace Operations – batch replace multiple files
http://wordribbon.tips.net/T011136_Saving_Find_and_Replace_Operations.html