How to forget Wi-Fi Networks
This article will show you how to forget Wi-Fi networks on your MacBook without an Admin password.
1. Navigate to Launchpad on you MacBook and search for Passwords in Search bar or click on the relevant icon, as shown below.

2. New window for Passwords app will open. Type in your Mac password or use Touch ID to gain access to the app.

3. In Passwords navigate to Wi-Fi section, as shown below

4. Right or Secondary click on the Wi-Fi network you wish to forget, as shown below and select Forget Network from the context menu.

5. Confirm your choice by clicking on Forget.

The Wi-Fi network is now forgotten and you are free to add it again, if required.