Create a custom role that can add but not remove reservation items
You can make a StageStock role that lets someone add items to a reservation but not remove them. You'll need the Manage User Roles permission.
- Go to Administration > User Roles.
- Click New role from scratch. Or open the closest standard StageStock role and click Duplicate, since standard roles can't be edited.
- Give it a Role name you'll recognize, like "Reservation add, not remove". Under Applies to, choose StageStock, then click Create and choose permissions. The area can't be changed later.
- Turn on Add Items to the Reservation and leave Remove Items from Reservation off.
- Click Save Changes.
Then give the role to the person: open their profile from User Administration, click Category Roles, and choose the new role for each category. They can then add items to any upcoming reservation.
Creating or editing a reservation itself takes Create/Edit a Reservation, a site-wide permission in an Administrative - StageStock role. Someone who can't remove items usually shouldn't have it, so have a manager create the reservation for them.