One of the more challenging concepts to understand about circle structure is this: A Circle is a special kind of Role
This means that a role can be expanded into a circle through governance, or turned back into a role in a similar way.
This article shows how to take a sub circle and turn it back into a role, while simultaneously preserving a role within that circle and moving it up to the super circle.
In this example we'll be collapsing the circle called "Sub Sub Circle" back into a role in the "This & That" circle:
Open a governance meeting and choose "Add/Edit Role" and select the Subcircle to be collapsed. (See: How do I start a governance meeting?)
In the resulting proposal we'll select 1) Remove this circle 2) we select "Keep Sub Sub Circle as a Role in This & That" (otherwise the circle and all roles within it would be deleted) 3) Retain "Role 3" (allowing TnT Role to be deleted)
With these selections we can expect that the supercircle "This & That" will have two new roles in it: a role named "Sub Sub Circle" and a role named "Role 3"
See the resulting organizational structure here:
Related: How do I remove a role?