I’ve changed my Wi-Fi password but my phone does not prompt me for the new password. How do I force it to stop using the old one.

On the phone......

Home Screen > Settings > WiFi

Tap on the blue "i" next to the name of the network

Tap Forget This Network

Then, Home Screen > Settings > WiFi > Select the network > Enter the new password

If the password is already entered, then you are saving your passwords in Cloud. You probably logged on from another device that is also using iCloud and the phone picked that info up and used the new password automatically.

On your phone’s WiFi settings, select the “!”

for the network …

… then select “Forget this network.”

When you attempt to reconnect you will again be prompted for your WiFi password.