To transfer messages from your Google@SAS account into a personal account, you will need to configure both accounts in a mail client, such as Thunderbird. After you have configured them, you will be able to drag and drop messages between the accounts.
If you are transferring messages to another Gmail account you can see the instructions here for configuring the personal account in Thunderbird.
You can also export and download your data from the Google products you use, like your email, calendar, and photos using Google Takeout. In a few easy steps, create an archive to keep for your records or use the data in another service. Instructions for using Google Takeout can be found here.