If you want to stop using IFTTT with your current WiZ home (to use it with another WiZ home for example), you can just tap the toggle button next to the IFTTT integration in the Settings of the WiZ app to disable the integration.

If you want to fully delete all link and data associated with IFTTT, this can be done by tapping on “Unlink” at the bottom of the IFTTT integration screen in the WiZ app.