Three versions of the same class

Summary

Need to retain class history

Content

Our Learn Center has three versions of the same Skillsoft "Getting Started with Word" course.  I now know this because after the "Getting started with Word" course was added to a Learning Plan,  a Learning Plan User reported that the Plan doesn't show that she had previously completed the course.

Upon investigation, I discovered the three versions, and that she did indeed complete the course.  

How do I eliminate two of the three yet retain the history?  Each version has had multiple users complete it.  

Thank you for your help.  Haven't been able to find an answer elsewhere.