hi

[CrashHopper]

how to leave a channel at IRC ?

and how to change my name ?

[Robo]

/part

[garib_admi]

/ns ajoin del #channelname
to delete the added channel.

[CrashHopper]

and how to change my name at
IRC ?

[Jafri]

/nick <name>

[CrashHopper]

without /ns ?
my account is registered so i will type without /ns ?
old name : Crash , new: CrashHopper

how to change then ?

[Blackbird]

without /ns ?
my account is registered so i will type without /ns ?
old name : Crash , new: CrashHopper

how to change then ?

Change your nickname to CrashHopper then use:
/msg NickServ group
So whenever you identify use CrashHopper or Crash (Both will work with same password).