When you design a logo using a logo tool, you are basically customizing a pre-made logo template designed by a professional graphic designer.
While you can make changes to colors, fonts, texts and add more shapes, the basic logo template can’t be changed.
Once you finalize the logo design, and checkout for download, it means that your vector logo is locked; you can’t make changes to it. That’s why it’s advisable to check your design thoroughly before downloading it for use.
If for some reason you still need to make changes to your vector logo, then you can contact Support and make a request for the edits. You may have to pay an additional amount for the change since an in-house graphic designer will make the required revisions for you.