If you need to undelete a client, click on Utilities, Undelete Client.
If you have security enabled, you will need the admin password for this feature.
Scroll or search for the client and check the X box. Then click OK to undelete the client to add him back to your client list.
If the deleted client was marked inactive, he will be on the inactive client list. You'll need to open the client card and uncheck the Inactive box on the right panel to move him to your active list.