You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, firstly can you please provide your name?

USER: I want to change my existing reservation, as most of my friends are travelling on other dates. Can you please help me with this?

ASSISTANT: Sure, I will help you with it. Before, please provide your name to check the existing reservation?

USER: Sure, I am Melissa Turner.

ASSISTANT: Yes, Turner I have searched in my database, but I could not find any previous reservation. Do you have any other requirements?

USER: No, thank you.

ASSISTANT: Ok, thank you for contacting our service. Hope you have a great day ahead.