screenpublishing is quite flexible on how you manage the number of players connected to your account, meaning you can add or remove players at any time.
If you are removing the player and want to also reduce the number of licenses you subscribe you will need to change the number of subscribed licenses after deleting the player.
Removing the player will also unpublished all the content for this specific device.
You can always re-connect the device using the paring code, but the device will be connected empty, with no content published to it.
To remove a player:
Click on the Player menu on the left side of the screen
Select the one or more players you want to remove
Click the Remove button on the top-right side