Change_accessibility

An Agent causes a Useful_location to become accessible (or non-accessible) to a Theme to a certain Degree. Instead of the Useful_location, the scene may be described with reference to a Portal (or part of the Portal, e.g., a door) to the Useful_location. They've blockaded the entrance -- no one can get in or out. Police have cordoned off the area where the crime occurred. The area has been barricaded to anyone but law enforcement officials.