If my catalytic converter is rattling and my exhaust pipe is rusted, do I have to replace both?

If my catalytic converter is rattling and my exhaust pipe is rusted, do I have to replace both?
Added (1). I've got a 2001 Honda CRV and the catalytic converter is rattling and I've lost a little acceleration power. Also, there's a fair amount of rust and the mechanic said the whole exhaust pipe/muffler would have to be replaced if I want to replace the catalytic converter. That's too expensive, is there a cheaper way?

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