iPad – Forgetting a Network
If your iPad keeps automatically connecting to the wrong network, you can “forget” the network and it will not automatically connect. You can always add the network back in if you decide you want it to auto connect again.
Click the Settings icon to open.
Select “Wi-Fi” in the left column. In the right column, click on the “i” (information) icon next to the network you want to forget.
Click “Forget This Network”. Choose “Forget” when asked if you want to forget the network.