Online Move Datafile in Oracle Database 12c Release 1

To check data files 
SET LINESIZE 100
COLUMN name FORMAT A70
SELECT file#, name FROM v$datafile WHERE con_id = 1 ORDER BY file#;

     FILE# NAME
---------- ---------------------------------------------------------
         1 +DATA_GRUP/AGAP/DATAFILE/system.267.955306645
         3 +DATA_GRUP/AGAP/DATAFILE/sysaux.271.955306735
         5 +DATA_GRUP/AGAP/DATAFILE/undotbs1.275.955306755
         6 +DATA_GRUP/AGAP/DATAFILE/users.277.955306777

To move datafile online
ALTER DATABASE MOVE DATAFILE '+DATA_GRUP/AGAP/DATAFILE/users.277.955306777' TO '+DATA_GRUP/AGAP/DATAFILE/users.dbf';

ALTER DATABASE MOVE DATAFILE '+DATA_GRUP/AGAP/DATAFILE/undotbs1.275.955306755' TO '+DATA_GRUP/AGAP/DATAFILE/undotbs1.dbf';

ALTER DATABASE MOVE DATAFILE '+DATA_GRUP/AGAP/DATAFILE/sysaux.271.955306735' to '+DATA_GRUP/AGAP/DATAFILE/sysaux.dbf';

ALTER DATABASE MOVE DATAFILE '+DATA_GRUP/AGAP/DATAFILE/system.267.955306645' to '+DATA_GRUP/AGAP/DATAFILE/system.dbf';
note: we can even move system, sysaux and undo online 

To check data files 
SELECT file#, name FROM v$datafile WHERE con_id = 1 ORDER BY file#;

     FILE# NAME
---------- ---------------------------------------------------------
         1 +DATA_GRUP/AGAP/DATAFILE/system.dbf
         3 +DATA_GRUP/AGAP/DATAFILE/sysaux.dbf
         5 +DATA_GRUP/AGAP/DATAFILE/undotbs1.dbf
         6 +DATA_GRUP/AGAP/DATAFILE/users.dbf

note: you should check within rman with report schema

report schema;


move by using rman
copy datafile 31 to '/backup_rman/agap.dbf';
alter database datafile 31 offline;
SWITCH DATAFILE 31 TO COPY;
recover datafile 31;
alter database datafile 31 online;
report schema;

note: the change has ben done within rman