Has anyone changed midwife ?

I haven’t seen ‘my’ midwife since my 6 week booking appointment, at my 12 week scan and appointment and my 16 week appointment I had other midwives. My midwife is part time and only does 3 days a week, she is really hard to get hold of, it’s taken me 3 days to contact her just to change the time of my 24 week appointment. I don’t know whether to ask if I can change to a full time midwife? Has anyone ever changed midwife? Was it easy to do or were they funny about it?