A Verizon Wireless phone plan can be changed online, by calling customer service, visiting a store location or from the device itself. My Verizon allows you to view and make account adjustments from a computer as well as through downloading the self-service app on your phone.
The option to backdate the plan change is available to cover any anticipated overages and make use of the new plan features that may include additional airtime or data. Adjustments to pricing are displayed before you're asked to finalize any plan changes. A plan change can be done anytime during a contract and has no effect on contract dates.