I'm in process of sending queries out both to agents and publishers (the few that still take unrepresented queries).
Let's say there is an offer on the table from a publisher, but I want an agent to handle it. I would imagine there would be some urgency about getting a deal sealed (of course, I have no idea, this is just how I dream it). I have heard that an author with a deal already in the works has a much better chance of getting an agent's attention. If that were to happen, would I still go through the regular query process? Just change my hook to "I have an offer from Insertnamehere publishing house"? Even so, would it be so sure of a thing (of course, provided that the agent represented similar work -- I do do my homework and don't just spam queries)?
If you answer this question, great. If you don't, it's all good. It's sort of a random question and really, just me procrastinating from editing for a contest.
I got my agent this way. I had partials and fulls out when I got the offer from the publisher. Two situations here:
(1) If you don't have anything currently sitting at an agency, including a query, query them by email or mail but put that offer information at the top. Include your phone number and email.
(2) If you have things at agencies, even queries, email or call (seriously, call) the agencies and tell them, "Hey, you're looking at something. There's an offer on the table. Here's my number." Then wait for the calls. Most of them will not have read your query/partial/full and beg for 24-48 hours to read it before getting back to you. Enjoy the attention while you can, because it's rare in publishing.