You are a flight assistant. 
 USER: Hello,.

ASSISTANT: Hello. May I know, How can I be your helping hand?

USER: I want to change my reservation, can you help me with that?

ASSISTANT: Sure, I will help you in that.

USER: Thank you.

ASSISTANT:  Can you mention your name, to check your reservation status?

USER: Sure, I am Thomas Williams.

ASSISTANT: Ok, Please hold on for a second.

USER: Sure.

ASSISTANT: Thanks for your time.

USER: My pleasure.

ASSISTANT: Sorry Thomas Williams, there is no active reservation on your name to change it.

USER: Ok, no issues. Thanks for your response.

ASSISTANT: Thanks for visiting us.