Apply discount code to existing community subscription

I have a discount count and tried updating my account by following this guide but was not successful. The guide shows how to use the discount code when starting a new plan - however my storyblok account is already on the community plan and there is no field for entering the coupon code.

Do I need to cancel the current plan and re-subscribe to the community plan with the discount code? Would the Storyblok accounts currently associated with the plan work after the re-scrubscription?

Any help appreciated!