Thanks David and Stephanie -- the listing had been up for several hours, and the customer hadn't acted on it. The item was the best-seller in my shop, but made in a certain size that I don't ordinarily make. Since the customer dragged her feet on actually making the purchase, I'm letting the second person have the item, since she's the one that actually paid for it. I contacted both of them; thanked the purchaser for her order, with a (I hope) diplomatic suggestion that when an item is listed as "custom" or "reserved" it is customary that it be left for the one that ordered it, but since the one who ordered had had several hours to make the purchase and hadn't, she - the purchaser - was welcome to have it. To the one who ordered it to begin with, I convo'd her, told her what happened, and that I would still make her item for her if she was still interested -- but if I created another custom listing for her, she needed to act on it immediately or risk having the same thing happen. The material to make this item are becoming extremely scarce, even Etsy sellers are out of the material and have backordered it, so people are getting a little pushy about getting their hands on it....... :(
As I was typing this, the first customer convo'd me -- said she thought custom listings were "private". Guess she didn't realize they were still visible and"clickable" to the general public. Anyway -- I'm setting up another listing for her, with instructions to act on it without delay.....