How to change your network password in the keychain (macOS)
In most cases, after your password has been changed, you may need to change your password in the keychain. Here's how to do it:
1. Open up Keychain Access using the Mac's Spotlight Feature. You can access Spotlight either by clicking on the magnifying glass on the top right, or by pressing Command + Space on the keyboard.
2. Scroll down until you see either credential you want to change. Usually, printer names, or network drives would have an @ icon by the side of it, and WiFI credentials would have a pencil by the side of it. Double click on the entry.
3. Click on the Checkbox by Show password, this will take you to a diglogue box which asks you to authenticate. Enter your Mac local admin password.
4. From there, you can change the password, change that password to the new password that you have. That box is where your old password is. After that, click on Save Changes, and the changes should have been made.