Revolve around Document or Object Access ?

I'm trying to rotate a portion of a sketch.  

When using the rotate tool, it asks me what axis i want to rotate around.

I really want to rotate around the objects own center point Z axis and/or the origin Z axis (as the object is aligned to the origin).

If I'm understanding this correctly, I need a sketch line or part line to revolve around.

Steps would be:

1. Create a plan that bisects the desired rotation object
2. draw a vertical line which I want to rotate around
3. go back to the object and rotate around that new line

Does this seem the correct workflow?

Thanks
Ethan