A badly written application or other problems can cause applications to become stuck. The application is waiting for an event to occur that never happens. Or the handling of the event doesn't exit the application. These applications/calls can be removed using the bvr --terminate command.
The command takes the form of bvr --terminate type args. The type can either be voice_application or calls. Currently both types do the same thing and are just alternatives for each other.
The args is a comma separated list of either calls, application id's or durations. The calls begin with VC and specify particular calls on the BVR. The application id is the unique ID representing a specific application. The duration will remove all calls with a duration longer than the specified value (in seconds).
A list of calls and applications can be found on the BVR by running bvr --status calls and bvr --status voice_applications respectively.