[Mailman-Users] How do I "set delivery off" via email?

[PeteBell]

In just the same way as you can subscribe and unsubscribe from a 
mailman list by sending (for example) an email to:  
<mailinglistname-request at postoffice.com>  with the subject line:
unsubscribe <password> address=member at postoffice.com,  I was under the 
impression that you can suspend delivery of list emails by sending an 
email to the same address with subject line:
set delivery off <password> address=member at postoffice.com

Is that not correct?
If it IS correct, then why is it not working?

Cheers
Pete Bell, UK