You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I'm Nicholas Turner.

ASSISTANT: How can I assist you at this moment?

USER: I am planning to attend live concert at Houston, can you please help me with booking a flight ticket?

ASSISTANT: Sure, can you please provide your travelling dates?

USER: Sure, I would like to take off on 06/26 and return back on 06/28.

ASSISTANT: May I know your nearest airport codes of travelling?

USER: My source airport code is IAD and the destination airport code is IAH.

ASSISTANT: Nicholas Turner, there are no flights available on your provided dates.

USER: Ok, no issues. Thank you for checking.

ASSISTANT: Thank you for contacting us.