You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hi.

USER: Anna Mitchell here.

ASSISTANT: How can I assist you Anna?

USER: Please help me in making some changes in existing reservation, due to my busy schedule on my previously planned dates.

ASSISTANT: Please wait, let me check.

USER: Sure, I will be waiting.

ASSISTANT: Sorry to say, no reservation found under your name.

USER: It's ok, no issues. Thank you for helping me.

ASSISTANT: Thank you, have nice day.