How to Repeat execute codeunit with changecompany?

Hi All,
I saw the steps to upgrade NAV from 2009R2 to NAV 2013
there is a step to do Task 4: Step 1 Data Conversion
Since I have more than 50 companies, is there a way i can create code to repeat this? -->

same goes for this step -->
Task 11: Step 2 Data Conversion

I tried using CHANGECOMPANY code, but it only works for Table but not codeunit
is there a way to do so?
Thanks before