If you need to move the CALLME button to another location or simply need to re-configure it to use another WiFi router, there are two approaches. The simplest one is if you have an already configured and connected CALLME button. In this case, you can prepare it for the move on the "Configure Device" page: click on the  Move Device checkbox which will instruct the button to clear its WiFi configuration the next time it is pressed.  After pressing it, verify that the configuration has been cleared: when the configuration is cleared, a small blue led inside the button will light up. It indicates that the CALLME button is now ready to be configured, just like it was when you first received it.

If your button is not connected or is misconfigured, you will need to remove the battery cover first. When it has been removed, you will see the reset hole - marked with the red arrow in the image below.

Insert a paper clip in the reset hole and press it gently until you feel a click.

While holding the paper clip in the depressed position, push the top of the CALLME button and hold it for a few seconds. When the configuration is cleared, a small blue led inside the button will light up. It indicates that the CALLME button is now ready to be configured, just like it was when you first received it. Please follow the configuration steps to specify its new WiFi as you have done before.  As a reminder, the procedure is described here.