Changing redundancy for Disk Group solely used by ASM Instance

In our database environment, we have a disk group with NORMAL redundancy that was used when creating the ASM Instance.

ASMCMD> ls -l

State    Type    Rebal  Name

MOUNTED  NORMAL  N      ASM_DG/

MOUNTED  EXTERN  N      DATA/

MOUNTED  EXTERN  N      FRA/

ASMCMD> cd +ASM_DG

ASMCMD> ls -l

Type  Redund  Striped  Time             Sys  Name

                                        Y    ASM/

ASMCMD> cd ASM

ASMCMD> ls -l

Type  Redund  Striped  Time             Sys  Name

                                        Y    ASMPARAMETERFILE/

ASMCMD> cd ASMPARAMETERFILE

ASMCMD> ls -l

Type              Redund  Striped  Time             Sys  Name

ASMPARAMETERFILE  MIRROR  COARSE   APR 14 11:00:00  Y    REGISTRY.253.844862281

ASMCMD>

It needs to be changed to EXTERNAL redundancy like our DATA and FRA disk groups. Is it possible to change this for a disk group solely used by the ASM Instance? If so, where can I find the steps of doing this?