Before we proceed, Here are the advisement for changing mobile number: It will take effect within 2-4 hours. Kindly note that you may lose your voicemail message, call recordings as these will be deleted as soon as the mobile number change request is submitted. Voicemail PIN will set to default using the last 4 digits of your new number to setup password and greetings again. Call records for the old phone number will no longer be available on My T-Mobile. Shall we proceed? ___________________________________________ Just to set a proper expectations there will be a $15 processing fee plus taxes but no worries, As a one time courtesy we will be covering it for you.