I don't mind at all if you want to switch computer labs to a time that's more convenient to you. Of course, the lab you want to switch into must have some free seats. I think all you have to do is to go to the SSC, drop the lab you don't want, and then register for the lab you do want. Now, I haven't tested this arrangement but it seems to work for other courses. Have a go and let me know if it does or doesn't work.
If you're contemplating switching, just bear in mind the Worked Example sessions I mentioned in the e-mail I sent out last week. The WEs are quite different from the labs. You want to make sure you can attend at least one of the four WEs in a week (they're the same, just different instructors). So, don't switch labs and then find you can't get to a WE.