How to update a parameter not from GCS, but from the running airframe

I would like to set a value of one of the parameters that can be updated by the GCS, from my airframe code. It should be performed probably by publishing a Uorb message that sets parameters values. This should be done from my airframe attitude control module. I did not find in the code of the mavlink module that runs on the flight computer, some code that receives Uorb messages that “sets parameter”. The only update mechanism that I found is from Uart/Udp.
Is there a mechanism that supports this functionality?
Or currently this feature is not supported by the mavlink module that runs on the flight computer?