Yes, you can!
To add another store of the same Sale Channel (for example, another eBay store) it's not necessary to edit the first one.
You can simply add a new store, clicking again on the relative icon on the left side of the Marketplace page.
You'll then be able to enter a custom label to recognize the same marketplaces connections among all the others:
Read this article to find out how to edit your connected Marketplaces: