You can remove a slave host from a distributed system. You may want to do this if you used the host for test purposes and no longer need it in the distributed system.
TREX is still installed on the removed slave host. The host may still contain index copies and configuration files with information on the distributed system. However, since these configuration files are not consistent, the TREX instance on this host will normally not start any longer. You should therefore deinstall this TREX instance.