It's possible to rename modules in the 2. Search Settings view. In this example, "Leads" will be renamed to "Prospects" and will display as Prospects when the user performs the email association action.
Expand the Association Settings view and click on 2. Search Settings view.
Edit the Leads module.
Type the new module name in the CRM Object Label field and save and close the document.
Check the 3. Select Associations view and confirm the renamed module is selected in all association types. Save and close if required.
Once these changes are pushed to the user's mail file using the Update All button, they will see the following "Find by" search options when clicking on the Select button
Search