Replication: does it work in both directions?

[Rich Wales]

I'm using replication on a 2.3.9 system.

I know that if changes happen on the master system, they are propagated
automatically to the replica system.

But what happens if I make a change on the replica (e.g., by setting up
an account to access its mail through the replica's IMAP server)?  I
tried this just now, and the change is NOT propagating from the replica
to the master.

What do I need to do in order for changes made on the replica to get
copied over to the master?  Or is this simply impossible?

-- 
Rich Wales      ===      Palo Alto, CA, USA      ===     richw at richw.org
http://www.richw.org   ===   http://en.wikipedia.org/wiki/User:Richwales
    "The difference between theory and practice is that, in theory,
theory and practice are identical -- whereas in practice, they aren't."