You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I aid you for today?

USER: Due to some health concern doctor suggested me to take bed rest and not to travel long journey's in any manner, so can you please change my ticket reservation?

ASSISTANT: Sure, I will help you with that. Can you please help me with your name so that I can find your existing reservation under your name?

USER: Thank you and my name is William King.

ASSISTANT: Sorry to say this King, there is no reservations under your name to change.

USER: Ok, that's fine, thank you for your help.

ASSISTANT: My pleasure, thank you for reaching out here.

USER: You are welcome.