You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: Jeffery Garcia here.

ASSISTANT: How may I help you today?

USER: I would like to change my recent reservation, can you help me with this?

ASSISTANT: Sure, I am here to help you with that. Please wait for a minute.

USER: Sure.

ASSISTANT: Yes Garcia, your reservation is found. May I know your planned trip dates?

USER: My trip dates are 01/14 and 01/16.

ASSISTANT: Ok, can I know your airport codes?

USER: I would like to travel from DTW to PHX.

ASSISTANT: Please wait for a minute. Sorry to say that, there are no flight's available based on your travelling dates.

USER: Sure. That's fine, thanks for your information.

ASSISTANT: Thank you for reaching us.