Hello-
First, create a cold backup of the old database. I'm guessing that it's a 10.2.0.4 or 11.2.0.1 DB. Is the current database 32 bit or 64 bit? If 32, you will need a new 32 bit Oracle Instance of the same version as on the cluster, then you will upgrade that DB instance to 11.2.0.3. Cold backup again (11.2.0.3 backup), then install a new Oracle DB instance on a 64 bit box, don't forget the template, as v12 only supports 64 bit. Then you will need to restore the 32 bit backup to the 64 bit server, both 11.2.0.3. Be sure not to initialize the database when re-installing Enforce.
If 64 bit version, then install the same Oracle DB version on the new server, be sure to apply the database template, then restore the cold backup. Then you will need to upgrade the DB to 11.2.0.3.
Hope this helps.
Best,
Ryan