With the introduction of MNP (Mobile number portability) in India, now a subscriber can change his or her telecom service provider while retaining the original mobile number. The whole process is very simple and normally takes 3-4 working days.
In order to port the number the subscriber has to send an sms “PORT 123#######” to 1900. Replace ‘123#######’ with existing mobile number that you want to port. Make sure to send the sms from the number that is to be ported. In reply to the sms you would receive an UPC or Unique Porting Code from the number 1901. Along with UPC number you would also receive an expiry date for using the UPC in the “UPC expiry date” in MM/DD/YYYY format in the sms. Once you receive the UPC you can walk into any outlet of the new telecom service provider along with your address and identity proof to get a new sim with your ported number.
There would be a brief ‘no service period’ of about 2-4 hours and then you can make and receive calls on your new sim from the changed telecom service provider. Also make sure to end your balance talk time before moving to new service provider as the same would not be carried to the account of your new telecom service provider.