You are talking about "steam_id"'s generated through a plugin that checks your hardware. such "unique" id's where used on non-steam servers to identify users.
This is easily fakeable by spoofing your hardware, so utterly useless.
If i remember correct i already told you in another thread that you should get STEAM cs1.6, especially your server should be STEAM OLY, this solves your problem with "changing steam_id's"
Real STEAM_ID's are UNIQUE, they NEVER change for NO reason. This is the reason why STEAM was created. Stop complaining about the limitations of problems from your illegal software.
EDIT: thinking about your words a little more makes me think that you want to change your hardware-id, means you want to plpay on a non-steam server again that banned you, or you want to make sure that you cannot be banned from a server you wnat to visit. sounds pretty funny....