Hi David,
Using the updateReportContent.py, you might get what you need. You can look at the following example:
https://github.com/xavierBizoux/viyaRestPy/blob/master/Examples/DevOps/update_report.py
I've not checked the code but it should not delete the report but just update the report content.
I'm quite busy those days but I can try to help you in the coming days.
Please let me know if you need help.
Regards,
Xavier