You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you?

USER: Mark Hill here. Due to inconvenience of my work, I want to change my reservation. Can you please help me for that?

ASSISTANT: Sure, we will help you. Wait a minute.

USER: Ok, I will wait.

ASSISTANT: Thanks for waiting, there was no reservation found on your provided name.

USER: Anyway, thanks for the information.

ASSISTANT: Thank you for reaching us.