/s_noid               Auto-reassign synth's ID to a reserved value

[
  int - synth ID
] * N

This command is used when the client no longer needs to communicate
with the synth and wants to have the freedom to reuse the ID. The
server will reassign this synth to a reserved negative number. This
command is purely for bookkeeping convenience of the client. No
notification is sent when this occurs.