How to disconnect a Wifi connection instead of using "forget" connection Suppose I want to disconnect to Wifi connection 'A' so that I can connect to Wifi connection 'B', how do I go into doing it without using the "Forget" connection for Wifi connection 'A'?
There is a Simple way to achieve this.

we have two cases in our hand.

Case A: When The Wifi connection 'B' is already in the Remembered (Saved) List in your Device, then you have to just Open the Wifi -> Just Click on the Wifi Connection 'B' from the list. and it will automatically get connected to it.

Case B: When The Wifi connection 'B' isn't already in the Remembered(Saved) List in your Device, then Open the Wifi -> Just Click on the Wifi Connection 'B' from the list, and you will be asked for the password and then If the Signing process goes well. you are now connected to the Wifi connection 'B'.

Hope this help you.

Izzy's note:  Whenever you connect to WiFi B while a connection to A is active, the latter connection will be canceled (disconnected) automatically as there only can be one WiFi connection active.