You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you?

USER: I am planning to attend my parent's anniversary party, could you book a ticket for me?

ASSISTANT: Can you provide your airport codes please?

USER: My airport codes are LAS and BOS.

ASSISTANT: May I know your travelling dates?

USER: I am departing on 06/11 and returning on 06/13.

ASSISTANT: For booking purpose, May I know your name please?

USER: My name is Donald Wilson.

ASSISTANT: Sorry Donald, there are no flights with your requirements.

USER: No problem. Thank you for assisting me.

ASSISTANT: Thank you for approaching us.