Change phone plan

[Melanie25]

I'm trying to change my phone plan and every time I go in and put my SIM card number in.It keeps telling me that it is an invalid SIM card.My phone is working so it can't be invalid

[Handy1]

@Melanie25  Log into your public mobile app and tap “manage subscription “ then tap “change subscription “ then you can choose the available plans to you to switch to you don’t need to enter your SIM card number as existing customer that’s just for your initial activation of physical SIM card 

add also once you find plan you like be sure to use the change in renewal option and don’t do immediate plan change to save money on your current subscription cycle