Follow these instructions provided by Google. Google Takeout is the recommended method of transferring content from your @wfu.edu to your @alumni.wfu.edu account.
BackUp Gmail for Mac
For students with a Mac computer, we recommend purchasing BackUp Gmail from the App Store. It is a lightweight Status Bar App that works in background, connects automatically with your accounts, and backs up any new message. More information can be found on the developer’s website: http://backupgmail.m4ss.net/
Please note that this is a recommended solution, but is not supported by Wake Forest University. Any issues or questions should be directed to the developer at firstname.lastname@example.org.