You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you?

USER: Can you please help me to book a flight ticket from SFO to IAD to meet my family?

ASSISTANT: Sure, may I know your travelling dates?

USER: I will leave on Oct 18th and return on Oct 20th.

ASSISTANT: Is there any connection limit?

USER: No, I prefer direct flight only and I don't want any other specifications.

ASSISTANT: Ok, let me know your name please?

USER: My name is William Gonzalez.

ASSISTANT: Sorry, there are no flights running currently with your preferred dates to travel.

USER: Ok, no problem in that. Thank you.

ASSISTANT: Thank you for reaching us.