how to patch changes to an rpm file

I have a third party rpm (rabbitmq-server-3.5.4-noarch.rpm) and I need to make some text changes on a static-file (a text file) in this rpm as per my organization policy. I need to make changes before installing it on my server. Could someone guide me to do this.

I tried rpm2cpio command but was only able to see the contents displayed on the console, but I need to make the changes to the text inside the rpm.

Solution

afaik there is no way to patch an rpm as such. I would recommend to:

get the source rpm (.src.rpm)
install the source rpm
patch your license text file
rebuild a new rpm (preferably with another version number)