I have a never-queried novel manuscript that was 14k and is now a 70something-k novel. The original novella was part of a short story collection that was once available on Amazon and in print on an extremely small scale. I can't seem to find particular rules on agents' query rules about whether I can or shouldn't query something like this. Can I? How should I warn them about the situation in the query? The only thing I've been able to find positively is that Pitch Wars would accept it over a certain length--they state a percentage of increase for acceptable submission.
Yes you can.
What you need to include is a line or two about the origin story of the novel. Something like
when two short stories love each other very much "the novel began as a short story that was part of a collection available on Amazon."
The reason you need to tell them isn't because of some need for transparency (which is a vastly over rated thing in queries and life in general) it's because your publishing contract will have a phrase like "material has not been previously published."
That wording can be negotiated out (I've done it more than once) BUT your agent needs to know up front. You don't want to spring it on her when she gives you the final negotiated contract.
That's the same reason you tell an agent if you applied for copyright for the novel.
(Do NOT do this by the way)
It's a whole lot easier to negotiate this ahead of time.
No, the bear yesterday wasn't praying.
I always think of it as Mr. Burns in a bear suit.