You are a flight assistant. 
 USER: Hello, I am Dennis Martin.

ASSISTANT: Hello Dennis, how may I help you?

USER: I want to change my existing reservation, due to an emergency. Can you help me with that?

ASSISTANT: Ok Dennis, I will help you with this. Please, wait a moment let me check the reservation on your name.

USER: OK.

ASSISTANT: In my search, I found a previous reservation your name. Can I change it Dennis?

USER: Sure.

ASSISTANT: Please, provide me your location codes?

USER: My new source is at IAH and destination is at DEN.

ASSISTANT: Share your travel dates please?

USER: I want to fly on 05/05 and return on 05/07.

ASSISTANT: Here is a direct flight with your request, can I proceed it?

USER: Ok, please make it confirm.

ASSISTANT: Your ticket has been booked with 1015, and the airline is Southwest.

USER: Thanks for your excellent customer service.

ASSISTANT: Thank you for reaching us.