Multiplexing control file in ASM

+ Edit the spfile with new ASM disk group location.

select name from v$controlfile;
alter system set control_files='+BW_CONTROL_01/TESTDB/controlfile/Test_control.ctl', '<New Disk group>' scope=spfile;
commit;

+ Start the db in nomount and verify the locations.
shut immediate
startup nomount;
show parameter control_files

++ Restore the controlfile from old location to new location using RMAN
rman target /
restore controlfile from 'Old_Controlfile_Location';

++ Change the sp file with correct file name of controlfile with location.

alter system set control_files='Old location','New file copy location' scope=spfile;

++ Restart the DB
shut immediate
startup