A renew course with a qualification outcome

Summary:

The outcome of a renewed course don't renew also

Content (required):

For example, I need my employees will have every 6 mounts a course in safety, After they finish the course they get a qualification in safety ( as part of the course outcome ).

The question is how can I define that the qualification depends and change every time the employee gets into the course?

I define the course like this-

there is a place to determinate the expiration date. But because it's on the course level and not in the offering - it will be static and change every time the learners do the course.