You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Gregory Martinez.

ASSISTANT: What type of service you are excepting from us?

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, I am happy to help you with that. Can I have your dates of journey?

USER: Actually I had planned my journey on end of September month, first of all please check if there is reservation available of not.

ASSISTANT: Ok, please wait for a while, I will check your previous reservation.

USER: Sure, take your own time and provide the information.

ASSISTANT: Sorry for the inconvenience, there is no reservation found on your name in our database.

USER: Not and issue with that one, I think it is not booked properly on my travel dates. So, it is not showing in your list. Thank you for your information.

ASSISTANT: Thank you for choosing us.

USER: Most welcome.