vba error ambiguous name detected: RangetoHTML

I am having an this error message come up: vba error ambiguous name detected: RangetoHTML, when I attempt to use the same code to create a email macro on the same sheet.
I use a ActiveX control button with this code. I need both macros on the same sheet/tab as one email is a review email and the second email is to create the final email. I used the exact same code for both macros.

From googling, I understand issue roots from the second use of the function needing to be named something different from the function used in the first macro--> which is where my question lies: how can resolve the ambiguous name detected error message with RangetoHTML?
I have tried to rename the function myself, but that did not let the rest of the code work.
Much help appreciated for a beginner in macros.

Error occurs where: Function RangetoHTML_SelectionChange(rng As Range)
[only second part of my code was pasted since part i could not submit]