If you are on a wait list, you will be moved automatically into the class if students ahead of you drop out of the course or if the enrollment capacity is increased by the school. MyUCLA will not let you know that you have moved off the wait list, so it is your responsibility to check your wait list status, which can be done via MyUCLA. You must drop yourself from any wait list if you no longer wish to be enrolled in the class.
Professors cannot add you to a class off of the waitlist (so please don’t ask them). Whether you are added to the class depends on your position on the waitlist, the size of the class, how many people drop and is the popularity of the course. Generally, students typically do not drop seminars after second pass.
With the exception of waitlists for experiential courses, which are handled manually by the Records Office, waitlisted classes count towards the units you’re allowed during first and second pass.