You can update the Scope from the Manage Scopes page (Apps → Manage Templates → Scopes tab).

In order to Edit the Scope:

1. Open the Manage Scopes page.

2. Find the Scope you wish to update and click on it.

3. Make the changes.

4. Click on the Update button.

Alternatively, you can edit the Scope inside the Create Template dialog by clicking the Edit scope button.

After clicking the Edit scope button the Edit {Scope name} scope dialog is opened.

Make the changes in the scope fields and click the Save changes button below the Groups field.

There are some peculiarities in the case of the Scope editing using the Team-Managed project types for scopes. Learn more about it here.