In version 6:
1. In Mail or Reports, open the saved report or mailing.
2. Select File > Save As from the menu bar.
3. Enter a new name for the copy and click Save. The same parameters are copied with the new name.
4. Delete the old saved parameters if desired.

In version 7:
1. In Mail or Reports, right-click the saved parameter.
2. Select Rename.
3. Enter the new parameter name and click Save.