Nginx version upgrade in already created docker image

I have single Docker image which has jetty, nginx and filebeat running in it. Now i want to upgrade the NGINX version but i dont have a Dockerfile from which base image was created.
I have tried to create Dockerfile from image but that didn’t help because the person who made it has used another image ID in it and i don’t have that image too.
Kindly assist how can i update nginx version in that image.

I have tried like that but that didn’t help as it gives “yum not found error”, as base image don’t have yum in it

FROM java-app-high:latest
RUN yum install nginx -y