Making a change note active
If change tracking is enabled, you can only make changes in the model when a Change Note is active. Each user's active Change Note is stored in the registry of their computer so that each user of a model can have a different active Change Note.
To make a change note active
Right-click the Change Note you want to make active, and then click Set Active.
Alternatively, from the Change Tracking tab:
• In the drop-down list, select the Change Note you want to make active.
• Click the 
Set Active button, and on the Select Object dialog, select the Change Note you want to make active.
Set Active button, and on the Select Object dialog, select the Change Note you want to make active.If change tracking is enabled, changes you make in the model will now be recorded against the Change Note you have made active.