you'll have to come back a day before the flight leaves to check for cancellations什么意思啊？

里面的 check for cancellations什么意思？看不明白？希望好心人给解释一下

If you want to book a round-trip ticket,you'll have to pay ( ) $80 If you want to book a round-trip ticket,you'll have to pay______30 dollars. 翻译you'll have to live with the knowledge that you sent an honest man to die I have no idea __he'll lend his tool to you.A,if B,that if things get difficult,you'll have to grit your teeth and I'll be glad cause I was blessed to get to have you in my life I'll be glad cause I was blessed to get，to have you in my life If you want to book a round-trip ticket, you’ll have to pay _____ $ 30. I'll go back tonight and go to company first. Tonight is I have time, I'll call you. we 'll have to get more then