Belgium did exchange one residence card for another?

Hi there,

I was living in Malta with my partner for years and now we move to Belgium. I already have my Belgian E card (I'm Italian) but not my partner. Asking on the commune, they told us that she need to start a process to get the residence here because she's a third-national (non-EU) citizen.

Why they just exchange her Maltese ID for a Belgian one? Somebody knows if the process to get her residence should be made on this way?

If someone knows a lawyer specialized on this field with knowledge on EU citizens vs Non-Eu citizens subject and share the contact, I will be happy too.

Best

2 different countries. It doesn't work that way with a simple exchange.