I did it a couple of times. The first was pretty straightforward when I was starting a new round of IVF and didn't want the same nurse because I didn't think she was that capable. SGF was accommodating. The second time was towards the very end of an FET, right before the beta. I was even expecting a BFP (testing at home) but just couldn't bear to talk to my nurse anymore. I got a call back from SGF basically asking me to stick it out. Part of me wanted to be a good sport and keep her, but I just felt miserable at the prospect of having to deal with her again (she always seemed put out to talk to me, borderline unpleasant, and had made a lot of weird errors that I had just dealt with) so I insisted that they switch me. And they did. My advice: just take stock of your issues with the person, list them plainly to the nurse supervisor (they will ask, and it's good for them to know if their employees have bad attitudes or make a lot of mistakes--or if it's just not a good fit), and stick to your guns. This is an expensive and emotional journey, and you want to feel good about your team and quality of care.