Is it possible to DROP out and re-do the course in the future ?

Hi I'm asking this question for my girlfriend. She is currently in the third year of her Retail course at university. She passed the first two years but now in her third year she is struggling A LOT to the point where I'm worried about her. She might fail this year and I told her it would be possible to leave it, take a gap year and re do the course next year or perhaps do some kind of resits, Anyone got any idea about the possibilities? In case she gets like 30% in her assignments and fails. Thanks for any answers, peace