Dial your cell phone number 0890 short or 8-800-333-0890.
Tell the operator that you wish to change the tariff plan.
Confirm that you are the owner of the room, saying a code word or your passport details.
During the day your plan will be changed.
In addition, you can change the rate using the service "Mobile assistant" (if connected) by sending to the short number 111 to the SMS code of the tariff, or through the service "Internet assistant" (for him, you first have to register a password, dial *111*25#) on the website of the company "MTS".