I give it 4 days and then I call and/or start calling other stores/sources. I worked in high-end retail many years ago. To find an expensive item is NOT that hard for a customer. A manager is out (unless special circumstances) no more than 2 days in a row. Main offices/buyers are there 5 days a week, 9-5. Most retail stores are open 10-9 M-F and have the same or a tad shorter hours on the weekend. I NEVER took more than 2 days to find ANYTHING for a customer; and this was before stores had look-ups, inventory was on-line, etc. A SA can fine it IF they wish to put the time into it. Honestly, I think most SA's don't care to. If it isn't in their store, or takes more than 2 calls to find, they don't bother. Also, some SA's who have a list of customers tend to "spread the joy around". Meaning, you got the bag last time, now it's another customers turn and so on (if it's a popular bag). I've seen it done many times; then and now. Knowing this and knowing there are other options to finding what I want, I give specific SA's a chance and then I do it myself. I ALWAYS get the bag I want. I refuse to wait knowing the way it works.
I would do the legwork myself and reward the person who helps you by giving them the sale. FYI: I'm STILL waiting 3 weeks to 4 months for assorted "Call Backs" from some SA's. Needless to say, they will NOT get my business in the future.