You want to drop a pluggable database from a multitenant container database that is used...

You can drop the PDB only if it is closed.

You can drop the seed PDB, but you cannot create any other PDB within the CDB.

You can drop the PDB and keep the data files to be reused by another PDB.

When you drop the PDB, the data files and redo log files are automatically removed from the storage file system.