Changing the name of one of my My Passport for Mac external HD

I want to use 2 My Passport for Mac external drives to back up my iMac. Can I just change the name (below the icon) of one of them so Time Machine will know that they are 2 different units?

Yes you can. You can rename them exactly like any other file or folder: Click on it and press return on your keyboard to start typing the new name.

Thanks for your prompt reply!

I have the same problem and tried the solution listed, but it won’t work on my machine.