Many people turn off WiFi completely to disconnect from a network in iOS and this is something completely logical, since the option that allows you to disconnect without turning off WiFi completely is not too close to the view.
Actually iOS does not have an option that allows you to disconnect from a wireless network as such, but if one that allows you to tell the device that you forget a network and thus will not connect until we indicate it manually (and again to introduce the password).
Disconnect from a wireless network in iOS without turning off AirPort completely
This function is called Skip this network and find it is necessary to access the network information from the Wi-Fi for iPhone, iPad or iPod Touch section.
In particular the steps to disconnect a network WiFi on iPhone or iPad without having to turn off completely the AirPort are as follows:
1 go to settings – Wireless.
2 touch on the information icon (the blue circle with the letter i on the inside) of the network from which you want to disconnect.
3 turn on the bypass this networkoption.
4 confirm that you want to skip the network in the new window that is displayed by touching on the Skipbutton.
This is all with these four easy steps to your iOS devices will disconnect from that network that you do not want to use for any reason and not will be reconnected automatically.
That Yes, if at any time you want to use a network missed, will have to manually tell you to connect to it and re-enter the connection password, since the iDevice erased completely settings saved to the network.
This feature is very useful when, for example, you are in a room with several WiFi networks and device moves from one to the other. This can be very annoying and so ignore that functioning worse in that time may be a good idea to make connection more stable and stop jumping by well known networks.