Editing a copy of a report is affecting the original one

Summary

Editing a copy of a report is affecting the original one.

Content

Hi all,

Don't know how simple might be this question, but i've made a copy of a report to edit it's layout. Luckily only the layout was affected, because when editing the copy instance, the main report, even though in a different folder, displayed the same changes.
If I try to configure data, etc this might be extremely troublesome.

Is there a way to copy and edit without affecting the original one? What do i need to configure or how to workaround?

Thanks