To close a connection, use the Connection/Close menu item. A connection can be closed at any time, even while you're sending or receiving sound (the transmission will be rudely interrupted). If additional sound subsequently arrives from the remote host, a new temporary connection will be automatically opened.
Closing a connection discards any changes you've made to the connection options. If you'd like to later reestablish the connection with the same options, save the connection to a file before closing it.