To void a tendered shop card, what step must be taken?

To void a tendered shop card, the correct step involves first pressing the VOID button. This action is crucial because it initiates the process to cancel the transaction. The VOID button is specifically designed to reverse a completed payment, allowing the system to handle the necessary adjustments in both the transaction records and the inventory accordingly.

Once the VOID button is pressed, other system prompts or steps may follow to complete the transaction voiding process, but initiating it with the VOID button is the essential first step. This operation ensures that the shop card payment is properly undone, maintaining the accuracy of both the sales records and customer interactions.

In the context of the other options, keying in the original transaction amount or entering the amount remaining on the card doesn't initiate the void process and can lead to confusion or procedural errors. Notifying the inventory manager may be necessary in certain situations but is not a direct step in the voiding process itself. Therefore, starting with the VOID button is fundamental to ensure the correct handling of the transaction void.