When a new user is given an access and Send Notification Email is marked, an email is sent to the user. There is a way to change the email address on that email notification specially when that person no longer works on the company.
To do this:
1. As an Administrator navigate to Setup > Company > Company Information
2. Edit the Return Email Address field
3. Click Save.
The Return email address is used when emailing forms and reports from NetSuite.
If user (Administrator) does not enter an address, the original Administrator's email address appears in this field, and is used as the return address for all forms and reports emailed from NetSuite.