You are a flight assistant. 
 USER: Hi. I am David Rodriguez.

ASSISTANT: Hello, how may I help you?

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

ASSISTANT: Sure, I will help you in doing this.

USER: Thank you.

ASSISTANT: Please standby.

USER: Sure.

ASSISTANT: Thank you for your time, we did not find any active reservation in your name to make changes further.

USER: Ok, no issues.

ASSISTANT: Thank you for reaching us.

USER: Thanks for your effort.