Force.com IDE Developer Guide

Getting Started with the Force.com IDE
Developing with the Force.com IDE
Testing Code with the Force.com IDE
Deploying Code with the Force.com IDE
Getting Started with the Apex Debugger
Summary of Getting Started with the Apex Debugger
Set Up the Apex Debugger
Explore a Simple Debugging Puzzle
Manage Debugging Sessions
Apex Debugger Limits and Considerations
Apex Debugger Troubleshooting
Force.com IDE Release Notes
Useful References
PDF

Manage Debugging Sessions

Any of your org’s sandboxes can use the Apex Debugger licenses that you purchase for your parent org. Track and manage your sandbox orgs’ sessions in Setup.
  1. From Setup, enter Apex Debugger in the Quick Find box, then select Apex Debugger.
    Manage sessions on the Apex Debugger page in Setup
  2. If desired, contact the debugging user whose license you plan to revoke.
  3. To end the debugging session that you want to terminate, select Revoke License.
    The debugging session ends, and a license is freed up. The next user who initiates a debugging session consumes the available license. The user whose session you terminated isn’t prevented from starting future sessions.