You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I help you?

USER: Due to heavy snowfall, I have decided to postpone my planned trip. Can you please change my recent reservation details?

ASSISTANT: Sure, may I know your name please?

USER: Sure, my name is Richard Johnson.

ASSISTANT: We found a reservation in your name. Can I have your airport codes?

USER: Yes, my source and destination airport codes are DTW and DEN.

ASSISTANT: Help me with the trip dates?

USER: I would like to change my departure and return travel dates as 5th and 7th of July.

ASSISTANT: Do you have any preferences?

USER: I want to depart in the morning time and I need single connected flight.

ASSISTANT: Sorry, no flights were available at this moment.

USER: Oh! That's ok, thank you for giving the information anyways.

ASSISTANT: Thank you for reaching us.