If it is the billing name and you go to the Sprint store or call in and verify your security information the change is real time, immediate in the billing system. If caller-id is showing up incorrectly it will take 72 hours max for that to update.
I was wondering if it was possible to change my name on my account. When I first opened the account I signed up for E-Billing so I hadn't realized, until I printed the online bill recently, that my first name was spelled wrong. Is it possible for me to go into a Sprint store and change it? And if so, about how long before the changes take effect?