Huawei Y6s
Android 9.0
1 Find "Carrier"
Press Settings.
Press Wireless & networks.
Press Mobile network.
Press Carrier below the required SIM.
2 Select network manually
Press the indicator next to "Automatic" to turn off the function.
Press OK and your phone will search for networks.
Press the required network.
3 Select network automatically
Press the indicator next to "Automatic" to turn on the function.
4 Return to the home screen
Press the Home key to return to the home screen.