Is this currently an existing feature request?
Yes - Pricing Plans Request: Ability to Switch Plans | Help Center | Wix.com
Wishlist item
No way for a site member to upgrade their plan or switch plans.
What current pain point are you facing?
Currently there is no way a site member can change or upgrade their plans. If a user wants to upgrade their plan, they would have to cancel their current plan and then repurchase. This is terrible because if a site member has payed for the month and then decided to switch, they won’t be automatically credited for what they’ve paid already.
Do you have a current workaround that you’re using?
Theres no easy way to fix this. Any workaround would have to be manually tracked and done by me… and if I have lots of users, wont be able to keep track.
Describe the feature you need and how it would work. (Bonus points for mockups 
)
A feature to allow site members to “Upgrade” or “Downgrade” their plans (switch plans). Im not sure how this hasn’t been a feature already as Pricing Plans has been around for years.
How will this impact you?
This is a deal breaker for me and I wont be able to use Wix. There’s no way I can scale my business if theres no seamless way to get customers to spend more money!!!