This code system http://hl7.org/fhir/message-reasons-encounter defines the following codes:

CodeDisplayDefinition
admitAdmitThe patient has been admitted.
dischargeDischargeThe patient has been discharged.
absentAbsentThe patient has temporarily left the institution.
returnReturnedThe patient has returned from a temporary absence.
movedMovedThe patient has been moved to a new location.
editEditEncounter details have been updated (e.g. to correct a coding error).