Forums will be making significant UX changes to address key usability improvements surrounding search, discoverability and navigation.
To learn more about these changes please visit the announcement which can be found
you need to send an Update message from Service B, to Service A. Service A needs to implement a Handler, and an Update operation, so when it receives the Update message, it updates the value, with the value in the Update body, send from Service B.
Service Tutorials 1->6 are *really* helpfull understanding how to talk between services.