Leaving, demotion and dishonorable discharge

With very low numbers, “Antarian Rangers can ill afford losses, even at the height of the organization's membership” nevertheless, “the Antarian Rangers will not stop a member from leaving if he persists on parting ways”. Leaving the Antarian Rangers may not seem as innocuous as it sounds as it is akin to “desertion” – and therefore is likely to be preceded by dishonourable discharge.

“Good reasons” to leave the Antarian Rangers are generally, “retirement” or “discharge as a result of injury”.

Cases of demotion may include:

Taking on a bounty for a Jedi (unless the latter is understood as a dark-sider);
Killing a Jedi (same restrictions apply);
During the Imperial era, to be known as an ally, informant or agent of the Empire (by the same token, possible survivors of the Roshu Sune undercover terrorists were likely to have been cast out)
Intentionally killing another Antarian Ranger;

In addition, “any Antarian Ranger who commits overtly evil or cruel acts can be expelled from the group”, while “A Ranger may also be court-martialed for improper conduct or violating the rules of the organization, receiving a dishonourable discharge from the group before being cast out”.

At any rate, former Antarian Rangers are bound by secrecy regarding the inner workings of the organization as stated in Hero’s Guide “Like any other paramilitary organization, the Rangers are concerned about the organization's secrets, and they take steps to eliminate the problem if an ex-member is revealing more than she should.” The extent of the “steps” taken is not known, though the wording suggests the worst.

Sources: Hero’s Guide, The Force Unleashed Campaign Guide