How can I manage to implement Step 4 in the following scenario:

 step #1. A was master; B was slave.
 step #2. B detects a failure; promotes itself to a master.
 step #3. The cause of the failure is resolved and removed by admin.
 step #4. A becomes a new slave manually or automatically.

I know I should rebuild server A `from scratch'
if the cause is disk error or something.
But in some cases (e.g. NIC error), A's disk is safe and sound.

In such cases, I thought I could switch master-slave roles
even after the failover command, but manuals and mailing list
archives seemingly suggest not to do that.

My idea was to kill all slon daemons, drop all slony schemata from
both servers, pg_dump/undump from B to A if needed,
then to re-install the schemata with reversed roles.

Any alternative plans are welcome.
Thanks in advance,

Kazutaka