Hello @Dushyant, welcome at our community.

Too bad you're going somewhere else with your contract. But nice to see you here at our community.

You can find it under Tariff & Sim, click on SIM & contract at the top and scroll down to Numberportability, then go to “another provider” and last click on “release number” now.

Please also have a look at this thread:

Kind regards, Ines.