If you have written a manuscript wherein you created original characters, plot development, and theme, that manuscript belongs to you and should be cited in a book by the copyright symbol. Should you require more protection, you can register that copyright.
However, in most circles, copyright is respected. Even an editor cannot significantly change the nature of your manuscript without written permission. An editor DOESN’T rewrite material. If you are thinking of turning your first draft into a publishing company, let me stop you in your tracks. You should turn in your BEST draft, knowing that there is still work to be done.
Poetry gets very tricky. Every word, every punctuation mark is crucial and fragile. To present anything but your best is to turn it over to a subjective microscope whereby your true meaning may or may not be expressed. If you are writing poetry without knowledge of rhyme or rhythm, Dr. Seuss is a great way to get started. Poetry for children should follow the rules; adults can function with more abstract language.
An editor should honor your style and try to maintain your syntax, but sometimes there are alternative ways to accomplish the same goal. Keep your eyes wide open.