Knowledgebase: Wireless
How to Forget a WiFi Network on macOS
Posted by Jonathan Ingram, Last modified by Richard Watt on 26 April 2018 03:10 PM

How to forget a Wi-Fi network Apple's macOS

  1. Click the Wi-Fi icon toward the upper right of your screen in the menu bar. It looks like a pizza slice.
  2. Click on Open Network Preferences.

    Click on the Wi-Fi icon in the menu bar and then click on Open Network Preferences.

  3. Click the Advanced button.
  4. Click the Wi-Fi tab.

    Click on the Advanced button and then click on the Wi-Fi tab.

  5. Select the network(s) you'd like your Mac to forget.
  6. Click on the minus (-) button.

    Select the network(s) you want to forget and then click the - button.

  7. Click on the OK button.
  8. Click on the Apply button.

    Click on OK and then Click on Apply.

Source - http://www.imore.com/how-set-wi-fi-your-mac