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

ASSISTANT: Hello, how can I assist you today?

USER: Owing to an emergency, I want to change my reservation. Can you help me to change my reservation?

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

USER: Sure, I will wait for your response.

ASSISTANT: David Collins, there is no reservation found under your name to do modifications in that.

USER: Ok, no issues. Thanks for your kind assistance.

ASSISTANT: Thank you for choosing us.