You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Eric Lewis.

ASSISTANT: How can I help you?

USER: I have planned a programme with my friends in San Francisco and I am searching for flight ticket. Will you please help me with that?

ASSISTANT: Sure, can I know your travelling airport codes?

USER: Sure, airports codes of my travelling locations are DFW and SFO.

ASSISTANT: Ok. Could you tell me the travelling dates?

USER: My travelling dates will be on 11/19 and 11/21.

ASSISTANT: Sorry to inform you that there is no flight found matching your requirement. Thank you for reaching us.

USER: Thank you for your service.