Redefinition: timestamp with time zone to timestamp

In light of the big hassle we have experienced with time zone stuff, I am planning on removing the time zone from all columns - we use utc anyway. All of the values in the timezone are +00:00, so there is really no conversion per se, more of a truncate operation.

I am wondering if anyone has done this live using the redefinition package or another way?

I am expecting that perhaps I will need to create a new column using the cast(mydate_with_tz as timezone), then do something fancy afterwards.

thanks - dn