How to cancel an appointment

How would you go about canceling a hair appointment that you've already rescheduled? I havent been to this lady yet, and I don't want her to think I'm someone who flakes all the time. I'm just scared to say anything because I know how judgemental hairstylist can get about canceling an appointment. But my husbands check was short this week so I'm not going to be able to get it done now. I just dont know what to say 😞

I have to message the lady directly. It's not like I just call and speak to some random person. It's also a personal hairstylist so it's her own set up.