Definition: You are given a conversation between two people. 'Person1:' and 'Person2:' are used to separate their respective dialogues. You are required to assign a label 'formal' if there is an absence of emotion and a presence of questions anywhere within the conversation. If such pattern is not found assign the label 'informal'.
Input:  Person1:       Reservation Center , Air China . Can I help you ?  
 Person2:Yes . I'm coming to confirm my ticket .  
 Person1:        May I have your name , please ?  
 Person2:My name is Zu Ping . In fact , I have a reservation on Flight No . 125 for Zhenjiang , leaving Beijing at 2:00 p . m . tomorrow . Now I'd like to make a change of my travel schedule . Is it possible to change my booking to the day after tomorrow ?  
 Person1:        Certainly .  
 Person2:Do you have a seat available on the same flight the day after tomorrow ?  
 Person1:        Yes . You are reconfirmed on Flight No . 125 for Zhenjiang , leaving Beijing at 2:00 p . m . on January 15th .  
 Person2:Thanks a lot .  
 Person1:        You are welcome . 

informal