Duplicate PDB to same CDB

• clone

CREATE pluggable database pdb1_clone FROM pdb1;
ALTER pluggable database pdb1_clone OPEN [instance=ALL];

• check status

SET lines 200
column name format a30
SELECT INST_ID, CON_ID, NAME, OPEN_MODE, RESTRICTED 
FROM gv$pdbs
WHERE name='pdb1_clone ';