There is no need to, and it’s not worth the hassle!
Which lab section you are in only matters when taking (initial) lab exams. If you find you cannot take a lab exam during your enrolled section, just go to any other lab section (the same day) and take the test there. There is a small chance that, if you go to a session not your own, there will not be a seat for you; if that happens, just go to another section. With multiple sections during the day, you will likely find at leat one that has a seat available.
Even while waiting to add the course, you should participate in it. Exam dates for new adds are the same as other students, so if you do not keep up with the work, you will be at a serious disadvantage. Come to lecture; take a seat. Go to the ICS 21 Help Center so you can work on your lab assignments where help from a TA and a tutor is available. Yes, there is a very low chance that you will do the work and still not be allowed to enroll, but we do expect to be able to enroll all.
Through Friday of week 3, if you are a regularly enrolled UCI student (that is, not an Access student), to add this course, simply add yourself to the wait list for it via WebReg. The registration system will add you into the course when there is an opening, and will send you email (to your UCInetID) to let you know you have been added. It’s possible you will not be added; but, as discussed above, your chances of getting in are quite high.
If you are on the waitlist and decide you do not want to be added, do remove yourself from it.
For more information about how course wait lists work, see the Registrar's Waitlist Option web page.
If you want to add the course after Friday of week 3, you use the on-line Enrollment Exceptions system to request to add the course. The instructor, the Dean of the school of your major and the Dean of the Bren School (if different) all must approve the request for it to be granted.
Email the instructor that you have filed a petition.: The enrollment petition system does not notify the instructor when you file a petition, even when the instructor’s permission is required.
For information on accessing the Enrollment Exceptions system and other details, visit the Enrollment Exceptions Web page.
Access students can also add the course through Friday of week 3; see the instructor with your Access enrollment form in hand. (You cannot add the class via WebReg.) Access students will be added, space permitting, after all regularly-enrolled UCI students.
Through Friday of Week 2, just go to WebReg to drop the course.
If you wish to drop the course after Friday of Week 2, use the Enrollment Exceptions system to request a drop; the Deans of the Bren School and of your major must approve it. Do note: Not doing well in a course is not an accepted reason for droppping it after Friday of Week 2, and your drop request will almost certainly be denied.
...to pass/not pass or back again: Through Friday of Week 2, just go the WebReg and make the change. After Friday of Week 2, use the Enrollment Exceptions system to request the change; Deans, not the instructor, decide whether to grant the request.