You are a flight assistant. 
 USER: Hello, I'm Debra Miller.

ASSISTANT: Hello, how may I assist you?

USER: Can you please search a flight for me with single connection?

ASSISTANT: Sure, may I know your travel dates please?

USER: My travelling dates are from 12/18 till 12/20.

ASSISTANT: Ok, may I know your airport codes please?

USER: My airport codes are from DEN to SFO.

ASSISTANT: Ok, hold on for a moment.

USER: Ok, take your time..

ASSISTANT: Sorry Debra, there are no flights available on your requested dates. Sorry for the inconvenience provided.

USER: It's ok, thank you for your information.

ASSISTANT: Welcome. Thank you for reaching us.