How to change plans when members move back and forth between then

CB 2.4.3
4.3.1+build.2020.02.13.15.08.12.b504dddb8

We allow members to either pay for membership or work a certain number of hours for us. We have a member who had a paid membership, changed it at some point on renewal to a work hours membership, and now wants to change it back on renewal to a paid membership. The system isn't giving him that option (nor can I do it in the back-end, no surprise).

From other posts here, I'm guessing that the original paid subscription has been marked as upgraded, so it's no longer an upgrade option for the member.

How can I set it up so that members can go back and forth between plans over time as they renew?A parent/child schema won't do it, I don't think.

Set both plans to Exclusive then under the Workflows tab set "Propose plan for upgrades only if it is more expensive" for both plans to "No: It will be possible to upgrade to this plan (for free with pro-rating) if all conditions below and elsewhere are met" followed by "Propose spontaneously plan for upgrades" being set to "Yes". This should allow them to upgrade back and forth as needed assuming there are no other conditions blocking access to the plan (e.g. usergroup access, view access level access, or conditions).

I tried that and it didn't work. Attached is a screen shot.

You'll see the two subscriptions at the top, one upgraded and one expired. There is no option to upgrade to the upgraded one, renew it, etc.

The only condition is that there be a subscription (the list includes both of these and some others), and the state is not relevant.

That's from backend which has some extra management steps. Does it work fine on frontend? In backend I believe for this to work you have to delete one.

No, it doesn't work. Here's what we see on the frontend for this user:

Strange, that should allow them to go back to the previous plan. Did you set "Propose plan for upgrades only if it is more expensive" to "No" for both plans? Please PM (see signature for link) backend super administrator login credentials and will review the plan configuration.