I'm not really a consultant, but a client-facing business analyst working for a government contractor. Although my people/soft skills are pretty good, and I'm very tenacious, I'm getting really burned out on being a business analyst because I keep finding myself in situations like this. I'd love to know how people with really top notch soft skills would handle it:

Boss assigns me a ticket that I need to dig out requirements for. I look up the name of the (remember: external) requester, say he's Bob.

me: Hi Bob, I'm supposed to work on your ticket. Can I set up a time to chat with you?

Bob: I don't really know anything about that ticket even though it was submitted in my name.

me: Oh, okay. Do you know who I can talk to about it?

Bob: not sure, maybe Sarah?

Me: Hi Sarah, are you familiar with this ticket?

Sarah: not really, try Joe

Me: Hi Joe, are you familiar with this ticket?

Joe: Nope. Bob submitted it, maybe he can answer your questions.

Me: He says he can't. do you know anybody else who might have information about it?

Joe: Hmm.... Maybe Angela?

Me: Hi Angela, do you know anything about this?

Angela: Not a clue, have you tried talking to Bob?

Me: Hey Bob, me again. I haven't been able to find someone who knows about this ticket. Can you think of anybody else I can reach out to?

Bob: Not really. How about asking your director?

me: (not out loud) WTF, my director?

me: Hi Director, I'm trying to figure out who knows about this ticket and the submitter suggested I talk to you. Do you know anything about it?

Director: No, talk to Bob about it.

me: Hey boss, I tried really hard to find out who knows about this ticket but got nowhere. Literally nobody knows anything about it. Should we close it?

boss: No, we can't close tickets without the submitters permission. Keep trying.

me: Hey Bob. I still can't find anybody who knows about this ticket. If you don't know who knows about it, can we close it?

bob: No, we need it to be worked on.

me: shoots myself in the head