Please note that this guide only refers to reseller accounts.
1-grid is only able to downgrade/upgrade packages that we own. If you created your own packages in WHM and assigned them to a customer, you would need to change the package yourself.
Expand the options on the left-hand side of the account you wish to change:
You should see the option to “change plan” now:
You’ll see a box with a list of other packages you created. Choose the package you wish to assign to the domain.