Our policy is that if you miss a lab for any reason, this will be your dropped lab. There is no excuse that will allow you to reschedule your first missed lab other than an assembly exam in another course. See the syllabus for more details (shown below for your convenience).

From syllabus:
Your lowest lab will be dropped. But use this drop wisely, i.e., do not just skip a lab since all labs are important and your next missed lab may be unavoidable. If you need to miss a single lab, it’s ok; you can not make up the missed lab. (You should do this lab on your own.) If you have a valid reason for missing this lab, get documentation for your first missed lab and hold on to it. If you miss a second lab, you must show the professor (not a TA) written documentation for BOTH your first and your second missed labs. This documentation should be official and from a doctor, judge, etc., so that a make-up can be arranged. You must notify the professor prior to your scheduled second missed lab or as soon as possible after your second missed lab.

Labs must be done at scheduled times.

An average lab grade of 65% or higher is required to be eligible to pass the class!