I show my grandmother in my family tree, but then the same entry is two generations before?? My grandmother cannot be my great great-grandmother as well. How to delete it?
Examine the profile detail pages. On the wrong relationship(s) click the edit button to detach the persons from each other.
If you need more specific help please share your grandmother's profile ID. The PID is the code near her name at the top of her profile.
Just to clarify dontiknowyou's instructions, the edit button for relationships is the pencil-and-square icon to the right of the name or names.
Detailed instructions are here (but don't mention that the pencil-and-square icon is the Edit button):