SUMMARY

You are getting error : User is not a Business Partner/ User does not exist, when you are trying to create Charms request.

DETAILS

Ask any of your colleagues to create a  CHARMS request for you.

In the description mention: User: XXX (username and SAP ID) has access in SMP sap system, but when he/she tries to create a CHARMS request, he/she gets error " user is not a business partner". 

Select System Name : SMP

Component : SOLMAN

Refer the article to further know how to create a CHARMS request.