You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How may I aid you today?

USER: Myself Nicholas Nelson, I need your help in booking my flight ticket from SFO to DEN. Can you please help me to book my flight ticket?

ASSISTANT: Sure, I will help you with that. Can you please share your preferable journey dates?

USER: Sure, I will depart on 07/30 and return on 08/01.

ASSISTANT: Please wait for a minute.

USER: Sure.

ASSISTANT: I am sorry to say that there is no flight found under your details.

USER: No problem, thank you for checking.

ASSISTANT: Thank you for reaching us.