Deleting domain from account

[#1]

I have 5 domains which all have had their IPS Tags and Nameservers changed to PlusNet's but which are automatically renewed by through 123reg.
One of these domains is rarely used and I have set the option within 123reg's control panel to cancel on renewal date of 27.2.2011.
How do I go about removing this domain from the list within PlusNet as there is no direct option for this?
Should I reset the IPS Tag and Nameservers back to 123reg or raise a ticket?
Thanks

[#2]

No point changing the IPS tag as you will no longer have the domain anyway.
After the domain expires, raise a ticket and ask for the domain to be removed from your account and PlusNets DNS servers.

[#3]

Thanks Peter.
I'd near-enough guessed that'd be the case - just needed it confirmed.