Yes, you can waitlist it again.
FYI the problem with doing this is that the system is first come first served. So you will drop down below any members that waitlisted after you had originally activated it. And the waitlist process is opaque, so there's no way to know how far you dropped. You could be first in line or 500th, depending on the demand for your waitlist request.
And hopefully you also know that shorter waitlists are much more likely to fill than longer ones. If you are first in line with a seven-day waitlist and two days in the middle come open, they don't hold for you. They will drop down until any subsequent list can be filled, and if they don't fill someone else's list, they will remain available to book on the member website until either someone grabs them or your other days become available as well. Your list will fill only if every day that you have waitlisted for is available simultaneously.