If you subscribed through Roku, it is managed through your Roku account.
Once your trial is complete, you may select a different plan on your Roku billed hulu account, however individual add-ons cannot be added or removed from your subscription.
To change your plan, please follow the steps below:
Open the huluTV menu by pressing the back button on your remote.
Select the current profile to open the Settings menu.
Select Subscription.
Select Change your plan.
Choose the plan you would like by selecting Choose this plan.
Changes made will be completed immediately and your subscription billing period will now renew monthly on the date of this change. A prorated credit for the unused portion of your current subscription will be applied to the first charge.
Enter your Hulu PIN to confirm and select Confirm update.