Disconnecting From a Wi-Fi Network in OS X Without Disconnecting Wi-Fi
If you’re one of those with Wi-Fi issues in OS X Yosemite, you’re probably tired of turning Wi-Fi on and off. OS X Daily offers the best option.
When you press Option + click the Wi-Fi icon in the menu bar, you get all sorts of information about your Wi-Fi network, but most importantly, you also get the option to turn off. Just select this option and you will disconnect without turning off Wi-Fi completely, which will make reconnecting a little faster.
Disconnect Wi-Fi in Mac OS X without Turning Off Wireless | OS X Daily