L6 imei change
 

hi masters,
here i have some L6 mobile phones.they're not registered in our network IRTCI(432-11).Telecommunication company out here is not going to let them enter the mentioned net and the last resort is IMEI changing.
Then i need a perfect tool for doing that or at least i need info about this matter to see if it's possible and if yes what's the best way?
Do i need to replace any hardware part or it could be done by software methodes like imei patching!!!
thanks for your attention.
PS:I'm sure there're lot's of guys waiting for any possible solution.