Dropping out and reapplying

Yes, but you'd probably be better off just suspending your studies and then administering the course swap internally at the uni.

What do you mean?

Is your sole objective to start a new course at your current university, or do you want to apply to other universities as well?

I'm currently studying midwifery at a university but I'm unhappy with the university so want to move to another university to study midwifery. Cohort is small and there is a lack of support for students

Okay, it’s a bit clearer what you want to do now.
In that case, yes, you could withdraw and apply again in the next cycle. You’d have to list your previous incomplete study and your new choices may ask for a reference from what is your current uni.
As PQ has said, you don’t need to withdraw to submit a new UCAS app. You could start one whilst still enrolled and see what offers you get and keep your options open.