To reauthenticate a LinkedIn ad account that is integrated to Engagio, you can do so in Admin, Integrations.
Navigate to Admin, Integrations, and click into LinkedIn.
Click into the account that you want to reauthenticate.
Click Login with LinkedIn.
Enter your username, password, and click Sign in.
Thats it! You have re-authenticated your ad account and generated a new access token.
Note: the you will need to refresh the page to see the new access token.