You will be given a definition of a task first, then some input of the task.
In this task, you're given a dialogue between a customer and a flight booking agent with a gap in the conversation. Your job is to find the answer of the previous dialogue. Avoid using irrelevant extra information while creating the answer. The answer should be relevant to the question before the blank. If you fill the blank with a question, it should have an answer from the agent in the given dialogue. Fill the gap marked with underline.

customer: Hello, I am George Lewis. 
 agent: Hello, how may I help you today? 
 customer: I need your assistance in booking of a flight ticket, can you please check out is there any flight between Boston and Phoenix? 
 agent: Sure, may I know your boarding and landing airport codes? 
 customer: My airport codes are from BOS to PHX. 
 agent: George, on which dates are you planning to travel? 
 customer: I want to fly from 06/15 to 06/17. 
 agent: Please be online, I will revert you back. 
 customer: Sure. 
 agent: Flight-1027 from Frontier airlines is having vacancies, travel charge is about 100 and you will be having 1 halt. Shall I proceed booking? 
 customer: You can proceed. 
 __ 
 customer: Thank you. 
 agent: Thank you for choosing our service.
Output:
agent: Your ticket has been booked, have a safe flight.