Merely modifying a template may or may not constitute process improvement. Your template may have changed because of external reasons (your customer wants you to use a different template) that have nothing to do with process improvement. You should explain the rationale for modification, then you would have a stronger case to demonstrate process improvement.
Process improvement suggestions can come from any number of sources:
- Appraisal findings
- PPQA audit findings
- Lessons learned
- Employee suggestions
If you couple the source of the process improvement suggestion with the actual change, usually spelled out in the Process Improvement Plan, then you have the information you need.