How to configure the values as path(URI) variable in target endpoint(upstream url) without using pluggins in kong gateway

Hello Everyone… I have a requirement like need to pass the URI path parameter values as headers via postman and its dynamically pic the values at runtime for upstream url.


as per the above example need to pass the appname value as string(.i.e. customer,employee).
Headers: appname=customer

And also, How we can set request.headers variable in service endpoint.