You are a flight assistant. 
 USER: Hello, I am David Davis.

ASSISTANT: Hello, How can I serve you?

USER: I want to fly from PHX to SFO to meet my friend, can you please help me to book a flight ticket?

ASSISTANT: Sure, Please help me with your travel dates.

USER: My trip dates are 10/20 to 10/22.

ASSISTANT: Please wait a minute.

USER: Sure.

ASSISTANT: Sorry, No flights found with your preferable dates.

USER: Ok, not an issue. Thank you for your help.

ASSISTANT: Thank you for reaching us.