How to detach a card reader in the Gateway Manager
If a merchant will not use a card reader that has been assigned
to him anymore (e.g. because it got stolen, lost or returned), you
need to detach the card reader from the merchant in the Gateway
Manager.
Select the merchant from the list and click on the
“Detach card reader” icon.
Confirm the dialogue to detach the card reader.
Now the merchant cannot use the reader anymore. If the merchant
tries to use the reader, an error appears. See here.