If the editor is someone you're paying to help you with a project (e.g. a freelancer who's editing your novel manuscript before you self-publish it), then there's no big problem here: you don't have to make all the changes they suggest. Of course, you'll want to put some careful thought into any suggestions you're rejecting -- and if it's a spelling or grammar edit, you'll want to be very sure that your version,
rather than theirs, is the one you want.
In other scenarios, though, your editor is someone who works for a publication or publisher rather than for you. For instance, they might be the editor of a magazine that you've submitted an article to, or an editor at a publishing house going through your book manuscript.
Chances are, you'll agree with the vast majority of the edits. If they've changed some things that you wouldn't personally have edited, but that you don't mind altering, I'd suggest you simply go ahead and make those changes too.
Where it gets tricky is when you firmly feel that your way of writing something is the better way. Here are some ways you can respond:
If it's a small change...
If you've been asked to change something small, like a phrase or word, but you really prefer your original – then say so! The editor may well be very happy to let it stand.
If the editor seems to have misunderstood...
Editors aren't infallible, and it's possible that your editor may have misunderstood your intention with a particular section of your piece. You can drop the editor a note clarifying what you intended – though if the text is ambiguous, it's often revising it to make it clearer.
If the changes would take a lot of work...
Sometimes, editors propose making changes that are going to take up hours of your time. Depending on what you're writing, you might want (or need!) to push back on these. For instance, if you're a freelancer producing articles for a website and you've been asked to make really extensive revisions, you might want to point out that you'd need to be paid extra to do that much extra work.
If you feel very strongly about the changes...
Sometimes, you might feel so strongly about edits (either proposed ones or ones the editor has gone ahead and made) that you're willing to pull your piece completely. It's definitely worth negotiating before it gets to this point (e.g. would the editor be happy if you made some changes but not other?) – and it's also important to check your contract, if you have one, to find out if you're able to stop your piece from being
published without facing any legal ramifications.
When your work is going out into the world with your name on it, it's important that you feel happy with the words and ideas being ascribed to you. That may occasionally mean pushing back against an editor's suggestions – or even asking for edits to be reversed. Normally, though, you'll find that the vast majority of editors are easy and pleasant to work with. After all, they want the same thing as you: for your published work
to be as good as it can be.