Change column type macaddr to macaddr[]

Hello,

I am using PostgreSQL 9.6.6 on armv8l-unknown-linux-gnueabihf, compiled by
gcc (Raspbian 6.3.0-18+rpi1) 6.3.0 20170516, 32-bit

I have a table with column name mac type macaddr. I need to change it into
array of macaddr ( macaddr[] ) type. Among all others I did try below:

licenses=# alter table licreqm alter column mac type macaddr[] using
mac::macaddr[];
ERROR:  cannot cast type macaddr to macaddr[]
LINE 1: ... licreqm alter column mac type macaddr[] using mac::macaddr[...
                                                             ^
I believe there should be a way, I just do not know it myself. Anyone can
help me?

Thanks & regards,
Ertan Küçükoğlu