changing joomla access level for existing subscrib - by: shira

Hi,

I have a user subscribed to a certain plan.
Now I want to subscribe it to an additional plan.

the additional plan has a different access level, so I want the user access level will be modified.

How can I do that?

The purpose is to have a free subscription plan and paid ones.
When a user with a free subscription subscribes to a paid plan, I want his access level to be change so he will be able to access more articles that the free user cannot access.

Please advise,
Shira