A user assigned with the role of Store Manager/Owner also has the ability to receive appointments in the same manner that a user with an Associate role would.
In order to enable this, you must be a Store Manager of the store you need to modify, or a Corporate Admin.
To begin, go to the Store and select Store > Admin.
On the right under "Managers", find and select the Store Manager user that you want to modify by name.
Once in their profile, you should see a button at the bottom to select called "Manager Can Take Appointments".
Once clicked and enabled, the button should change to "Disable Manager Appointments".
When enabled, this user will now appear in the list under the Associates section of the Store.