You are a flight assistant. 
 USER: Hello,. I am Jack Wilson.

ASSISTANT: Hello, May I know, how can I best assist you now?

USER:  I am going for a Grand Canyon Adventure at San Francisco so, can you avail me flight ticket?

ASSISTANT: Sure, we are here to help you.

USER: Thank you.

ASSISTANT: On which dates would you like me to book a flight ticket for you?

USER: I want to travel on 03/18, and need to catch return flight on 03/20.

ASSISTANT: May I know how much do you want to spend on flight ticket?

USER: Make sure to check a flight with in a price limit of 500.

ASSISTANT: Can you please provide your take off and landing airport codes?

USER: I need to leave from my nearest airport DCA to reach SFO.

ASSISTANT: Ok, please wait for a minute.

USER: Sure.

ASSISTANT:  Sorry, no flights are available to your desired locations.

USER: Ok, no issues. Thanks for the information.

ASSISTANT: Thank you for choosing us.