Subject: Re: Can't belive I did that
Can you buy the NEW shares on Monday and reassign to that lot, which is not settled? Seems unlikely, I think the only way to be sure would be for somebody to try it.

If you think about it, it MUST BE POSSIBLE! What if you sold those call options without owning any shares at all? When you get assigned over the weekend, you can only buy those shares on Monday when trading resumes, and then deliver them.