I have a Public Mobile SIM and phone number. i want to keep this phone number -- but switch to Koodo

I’ve already gone to the store to purchase a Koodo sim card (I have it here at home with me).  I see that it has a phone number assigned to it already  that isn’t my Public Mobile phone number that I want to keep.  

SO - i have a Koodo SIM with phone number i don’t want. 

And a Public Mobile SIM with a phone number I do want. 

How can I get my Koodo SIM phone number corrected?

Thank you so much.