Closing
a Database Session Manually 
Use
In certain cases, it may be necessary to terminate an individual database session manually.
Prerequisites
The database instance is in the ONLINE operational state.
Procedure
...
1. Select the required database instance in the list of database instances.
2. Choose Instance ® Sessions.
3. Select the database session that you want to close.
4. Choose Actions ® Kill Selected Sessions to close the database session.
See also: