Migration - Drop FK and generate new column

Guys, I need to drop some references in 4 tables and create columns that
contain the data from the tables that are going to be decommissioned.
Was I
clear? :s

I was thinking in some migrations to perform the following steps:

Migration X
1.- Create the now column
2.- Insert the new info in the new columns recently created
update bookings a
set booking_status = (select status from booking_statuses b where
b.id =
3.- Drop FK

1.- Generate FK
2.- Point each FK to the corresponding record of the parent table
3.- drop the column booking_status of the example.

Any suggestions?