Need help with my elevator blueprint

I am new to ue4 and learning how to make some basic blueprints. Currently, i have some problems with my elevator blueprint.

If the elevator is on the second floor and the player is on the first floor, the player could call the elevator down to first floor. However, if the player gets into the elevator again after calling it down and want to move up, the elevator goes down instead of goes up.

My blueprint is attached below.
Box and Box 1 are the box collisions. The Chinese character is timeline. Box controls elevator and it is in my elevator, Box 1 is out of the elevator and it is used for calling elevator back.

I really need someone to help me out. Thank you in advance!