I had this happen with my current mat leave family ~ new family needed care 3 weeks before old family was leaving ~ I just explained that the new family needed care to start before they were slated to formally finish and was their any 'wiggle room' with their end date ... we worked out a schedule cause there were 3 days that current family NEEDED care due to appointments and did not want to give up the spot but the other days in that three week period they had family/friends and dad took some 'vacation' days to cover .... enrolling family found someone to help them with the 3 days that current client 'needed' care .... it was win win for everyone and I aim to find that solution when I can ~ if we do not put our 'needs' out there than we cannot complain when our needs are not met