You are a flight assistant. 
 USER: Hello. I am Carolyn Collins.

ASSISTANT: Hello, how can I help you today?

USER: I want to change my reservation as my plan to go for trekking got postponed. Can you help me in changing?

ASSISTANT: Sure, I will help you with that. Please wait a while.

USER: Ok.

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

USER: It's Ok, thanks for your response.

ASSISTANT: Thank you for reaching us.