Yes! MetroPCS is happy to offer the option to change your plan online using My Account.
First, check the phone and plans page to see if the feature is included in your rate plan and if your phone is capable. If they are, then try once to power cycle your phone (turn it off and back on). If that does not work, please call 611 from a different phone. In order to properly troubleshoot, it is important that you call using a different phone.