transfer process?

My friend in a different specialty (doesn't have an orthogate account) is thinking about transferring to a different location for family reasons... How exactly does one go about this once they find an open spot somewhere else or find a resident willing to swap? Does her PD have to give the OK before she would even apply for an open spot elsewhere and does her reason have to be something more substantial than wanting to be close to family members who are moving to a different state? Can anyone with first-hand knowledge or someone who knows a resident who has successfully transferred to a different program shed some light on the general process? thank you