May I speak to Kate? I'll call back later.

Hello?
Hello. May I speak to Kate, please?
Sorry, she's not here. Who's calling, please?
This is Mike, Kate's friend.
Hi, Mike. Can I take a message?
No, thank you. I'll call back later.
Okay, bye.
Bye.

Hello?
Hello? Can I speak to Kate?
Speaking.
Hi, Kate. This is Mike.
Hi, Mike. What's up?
Let's play badminton at the park.
Sounds good. What time?
How about at two?
Okay! See you at two.
Bye.