Is it possible to install OBIEE 12c on container database?because it is giving error while installing obiee12c on container database.if it is not possible then is there procedure to convert the container database to pluggable database?
No, it's not possible to use a container database (CDB) as target for the Repository Creation Utility step (RCU). You need to have access to a pluggable database (PDB).
Don't try to convert the CDB into a PDB. The CDB will contain your PDBs. What you have to do is to create a new PDB and use it during the repository creation.