I pitched to Agent A at a conference in August, and his agency partner, Agent B, at the same conference. At that pitch, I told him, "Agent A already saw this and requested more." He told me there was no need for him to look if Agent A was interested, so we talked about random writing stuff. I went to another small conference in November, two days after I got a final rejection from Agent A, and Agent B was there. By a total fluke, I had an appt with him, so I sat down and said, "I just got a rejection from Agent A, but I'd love to get your input on how to build platform and work on marketing." It was a very valuable conversation, and he ultimately told me that once I get my platform to Levels A B and C, to send him a query, even though Agent A declined it.
I look at it this way: It's your time. Use it to ask questions or chat about the industry or ask them to look at your query and see if they have suggestions on how to strengthen it.