Recovery key set by my "company, school, or institution" on private laptop
This Apple discussion says:


  After a couple of exchanges with our engineering team they have recommended two things you may try.
  
  The first solution is as follows:
  
  
  Disable FileVault
  In the system directory, go to "/Library/Keychains"
  Move the files "FileVaultMaster.keychain" and "FileVaultMaster.cer" to the Trash.
  Deleting the files should then allow you to enable FileVault on the system and provide a recovery key. Refer to article http://support.apple.com/kb/HT5077 if you have questions regarding the location of the files.
  
  
  Second solution:
  
  Performing an erase and reinstall of the computer system will reset the master password and allow you to encrypt the drive again.