You can go to the Payroll Tax Information section to edit the email address of the signer of the W-3 form in QuickBooks Desktop (QBDT), ATX Bookkeeper. I'd be happy to guide you through the process:

1. On your QBDT account, go to the Company menu at the top.
2. Choose My Company.
3. Click on the Pencil icon.
4. In the left menu, choose Payroll Tax Information.  Be sure you click on Payroll Tax Information on left menu!
5. Select Auto-fill button.
6. Enter the correct email address, then Click OK.
7. Be sure and click on the Auto-fill button when you are in the Payroll Tax Information section - I missed it the first time through, but then re-read the instructions from a later post and figured it out!