If your password has already expired, you won't be able to log into VPN in order to change it via Enterprise Connect. 

You'll need to go to pm.interpublic.com, log in with your full email address and expired password, and follow the prompts to change your password there.

Once that is completed, your computer login password will still be your old expired password, and we don't want that, as it is annoying and could cause a lot of issues down the line. 

So, follow the instructions at this link in order to get that lined back up:  Re-sync Mac login password and Network/Email password