Phone Lock Code

[Jax]

I even do not remember setting it, but as I upgraded my phone (and Fido sales person deactivated my old Sim before transfering my data to new phone), my oldd phone keeps asking for "phone lock code".  Does anyone know how to reset phone lock code without old PIN?

***Edited to add labels***

[FidoStephane]

Hi there Jax, 

What is the manufacturer and model number of your old phone?

What type of information are you attempting to retrieve from your old phone?

Is your SIM card inserted in the old phone when you receive the 'phone lock code' request?