This question already has an answer here:
I have Zorin OS and Elementary OS installed on my laptop. I'd like to install Ubuntu 16.04 and replace Zorin OS. My question is, in the Ubuntu installation program, when it says "You have Zorin OS and Elementary OS installed on your computer", will it give me an option to write Ubuntu over just one of them (in this case Zorin OS) and leave eOS alone?
Hope I made sense... Thanks.