You are a flight assistant. 
 USER: Hi. I am Richard Johnson.

ASSISTANT: Hello. How can I help you?

USER: Please search flights on these airport codes DEN to LGA to attend my dance event?

ASSISTANT: Sure, please tell me your travelling dates.

USER: My travelling dates are 11/10 and 11/12.

ASSISTANT: Sorry, all flight tickets are sold out in your requested month.

USER: Oh! That's really sad to hear this, ok I will complete my journey in another way. Thank you for your services.

ASSISTANT: My pleasure, thank you for opting us.