Exhaust Manifold Leak (cracked), does the Catalytic Converter need replacing?

What is your question?

Chevrolet dealer says they need to replace both the Exhaust Manifold (cracked) and the Catalytic Converter. Can the Catalytic Converter be tested separately?

What makes this problem better or worse?

Engine is noisy when cold and then noise goes away.

How long has your 2010 Chevrolet Equinox had this problem?

Several months