You are a flight assistant. 
 USER: Hello. Joshua Campbell on this side.

ASSISTANT: Hello. What can I do to make your experience better with us?

USER: I want to change my previous booking due to my health issues. Can you help me?

ASSISTANT: Sure, I'll help you in changing an existing reservation. Please wait a moment I will check the reservation list.

USER: Sure, take your time.

ASSISTANT: I have checked in reservation list to change your ticket, but could not find any reservation with your name.

USER: Oh! That's very surprising to hear from your side. Anyways, thank you for checking.

ASSISTANT: Thank you for approaching us.

USER: You are most welcome. \.