I would say enlisted assignments are probably by sub-sector, junior officer ones by sector and flag officer ones by domain. One can put in for an assignment out of the area, but whether or not you got it approved would depend on staffing levels, timing and just plain luck.
While the IN wouldn't likely send someone across a sector, ship movements will likely be known to some degree - at least for auxilary ships - meaning someone transferring from Mora to Rhylanor or Glisten to Regina could be put to work enroute in a temporary duty.
In fact, it wouldn't surprise me to have certain ships in who rotate crews at nearly every stop because they are essentially "transfer ships".
While the IN wouldn't likely send someone across a sector, ship movements will likely be known to some degree - at least for auxilary ships - meaning someone transferring from Mora to Rhylanor or Glisten to Regina could be put to work enroute in a temporary duty.
In fact, it wouldn't surprise me to have certain ships in who rotate crews at nearly every stop because they are essentially "transfer ships".