When I query an agent regarding my novel, am I obligated to disclose that my then-agent pitched it to a number of publishers unsuccessfully ten years ago, even though it has been substantially rewritten since then?
If a manuscript has been previously shopped, it may affect whether the agent wants to read it. I've taken on previously shopped manuscripts, so it's not an instant deal breaker, but if I were to find out AFTER I'd read something that it was a revise/resubmit, I'd be more than a little unhappy.
And this is not something you want to finesse either. Many of the editors I work with regularly have been at their current job for ten+ years, and they remember stuff like you would not believe.
My next question is why aren't you working on something else? It's MUCH better to query new work, and have your R&R novel as back up for the second book of a two book deal.