You are a flight assistant. 
 USER: Hello.

ASSISTANT:  Hello, how may I oblige you today?

USER: I am Jack Evans. Owing to an emergency, I want to change an existing reservation, so please help me in changing the reservation.

ASSISTANT: Ok, please wait for a while.

USER: Sure.

ASSISTANT: Your reservation found, so please give your details for further process.

USER: My source and destination codes are IAD, IAH.

ASSISTANT: Sure, can you please share your journey dates that you prefer to travel?

USER: I want to fly on Feb 02 and return on Feb 04.

ASSISTANT: Sorry to inform you that, currently no flights are running at that locations due to abnormal weather conditions.

USER: Not an issue. Thank you.

ASSISTANT: Thank you for reaching us.