When you create packages, those packages are saved in the packages list. To make things easier, you can upgrade accounts with much more ease and less clicking. To do this, you only need to follow 4 steps.
1) Log into WHM by going to domain.com:2087 or Create.com > Sign in > Hosting > Reseller > Login to WHM.
2) Open/Search List Accounts
3) Click the + next to the domain cPanel you would like to update
4) Click "Change Plan"