How to drop a registred nick
First identify yourself to NickServ with the identify command, then issue
a /msg NickServ@service.de UNREG
NickServ will then reply with
-service.de- *** '<YourNick>' is unregistered.
For instance if a user name "gnarfer" does unregister his nick, NickServ
-service.de- *** 'gnarfer' is unregistered.