Technical Bulletin No 42 details our leaver / opt out processes.
What you need to do depends on how soon after joining your employee opts out:
Use Opt out to tell us about these employees.
Note: Excel spreadsheets should be sent to email@example.com (or firstname.lastname@example.org) using Opt out as the email's Subject:
Use our Leaver form
Leaver form Word Docs should be emailed to: email@example.com (or firstname.lastname@example.org) using the Subject: Leaver Form / Leaver Forms (### attached) and have a max of 10 attachments.