Depending on where you live (i.e., if in a major metropolitan area), there are definitely reputable luxury watch resellers locally who would absolutely buy your submariner back at MSRP + taxes, without hesitation. But if you flip it, you're absolutely going to burn your bridges at your AD (which might not be that big of a deal if you're a Seiko guy).

Don't work with bobswatches. I've heard that they're absolutely a ripoff for reselling.