I subscribed to Musicnotes Pro - Standard, but would like to upgrade to Musicnotes Pro - Plus - Can I do that?

Musicnotes Pro subscribers can manage their subscription from the "Musicnotes Pro Membership Details" link under the "My Musicnotes" section in "My Account".

From here, subscribers can:

1. View or change their Recurring Billing Payment Method used by default for their current subscription,
2. Switch the billing period frequency for the Musicnotes Pro tier they are currently subscribed:
   1. Monthly subscribers may switch to annual billing on their next Renewal Date,
   2. Annual subscribers may switch to monthly billing on their next Renewal Date
3. Cancel Membership
   1. If the customer cancels their subscription, they will receive the benefits of the Musicnotes Pro tier to which they are subscribed until their next billing date. At that time, their Recurring Billing Payment Method will no longer be billed.
   2. Customers that have clicked the Cancel Membership button will be able to restart their membership at any time before their Renewal Date.
4. Or, change the tier of their current Musicnotes Pro membership:
   1. Musicnotes Pro - Standard subscribers may upgrade immediately to Musicnotes Pro - Plus,
   2. Musicnotes Pro - Plus subscribers may change to Musicnotes Pro - Standard at their next Renewal Date,
   3. The Musicnotes Pro subscriber will retain the same billing period frequency.