To Delete Design History

Select File > Settings > Configuration > Configuration Variables .
The Configuration Variables dialog opens.
Select the MS_DESIGN_HISTORY configuration variable.
Click Edit.
The Edit Configuration Variable dialog opens.
In the New Value field, type delete=1.
Click OK, then click OK again to close the Configuration Variables dialog.
Verify that you want to save changes to the user configuration file.
Exit and restart Promis.e .
Do one of the following:

In the status bar, click the Design History icon and select Delete from the pop-up menu.

or
Select Drawing > Utilities > Design History > Delete .
Click OK to verify that you want to delete the design history.
The design history for the file is deleted.