You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Paul Walker.

ASSISTANT: How can I assist you at this moment?

USER:  Actually I am an old person and I don't know how to modify a flight ticket that is booked by my son in the last week but suddenly I got admitted in hospital with a typhoid fever, so I am unable to travel the trip and my son is busy in his office work. Can you please help me in changing my flight ticket?

ASSISTANT: Sure Paul Walker, I will help you with that.

USER: Thank you for your positive response.

ASSISTANT: Please wait a moment to check flight availability.

USER: Sure.

ASSISTANT: Sorry Paul Walker, no reservation has found under your name to change.

USER: Ok, that's fine. Thank you for your help in searching and providing the information.

ASSISTANT: Thank you for choosing us, have a good day.

USER: Welcome.