How to keep number of my old O2 Pay As You Go to another O2 Pay As You Go sims

[Alannnnnnn]

I have several O2 Pay As You Go SIM cards, and I want to transfer my number from one to another. However, when I try to use the PAC code via O2’s online form, it shows the error 'This can't be an O2 Pay Monthly PAC.' How can I transfer my number between two O2 Pay As You Go SIMs?

[Enlli]

Internal numbers don't need a PAC. You need to follow the MIGRATION process

Guide: Migration & porting into O2