If you want to delete, rename or change the picture of user, open the person profile and go to its “Settings.”
Under "People" section, you'll find all your saved user profiles. Click the one you want to select and then tap "Edit" button.
Now rename it or choose a new picture.
If you want to delete it, tap the cross (x) icon next to it or click "Remove" button. A pop up box will appear, click "Remove" button once again.