While you do not need a new license when switching to AutoPass License Server to manage your ALM licenses, you do need a copy of the license file.  If you no longer have a copy of your license that was sent to you at the time of purchase or rehost, either contact your support provider for a reprint of your license or follow these steps:  https://eyeontesting.com/answers/how-do-i-transfer-my-actual-alm-license-to-autopass-license-server/#gsc.tab=0