Using your query to help with manuscript revisions

There is a lot of advice on the internet saying to write your query letter well before your novel is ready. It can help you focus the novel, and it gives you time to get your best query letter together, so you don't rush it the day before you want to start querying.

All good advice. All advice that I've followed.

But if you're like me, sometimes you run into a problem. You work on your query, finally send it to CPs and get it somewhere you're happy with...and then you change a HUGE plot point i...