Mobile number portability was launched officially on Jan 20, 2011. Now you can switch from BSNL, Airtel, Tata Docomo, Vodafone, Aircel, Idea, Reliance to one another operator. The main reason could be lack of service or better plans in other operators and network coverage. You can switch between GSM and CDMA operators as well.
Procedure for Changing the Operator:
1) Send an SMS to 1900 in following format: PORT – eg. PORT 9123456789
2) You will get an SMS reply that contains a unique porting code.
3) SMS to the preferred operator quoting the unique code. This code is valid only for a few days, and one must apply again if it expires.
4) Your existing operator will check with new operator & if there are no dues then approval will be given for porting.
5) You will get an SMS on the time and date when porting will take place. Rules mandate that process be completed within 4 days of applying.
6) After porting is complete, wait for an SMS from your new operator confirming the switch. Your phone may be dead for about 2 hours when the porting takes place.