It depends on the quality of the speaker - check with polk. I went through my manufacturer and have had drivers re-coned a couple of times (simple procedure common in high end gear - studios, for example, damage speakers regularly, transport, dropped microphone, incorrect patch panel setting etc.).
For lower end stuff it is cheaper just to replace the entire driver or speaker as the drivers are not worth much and labor is costly.
I would not recommend you go through a third party unless they are approved by Polk. Neither would I recommend you mess with this yourself....the interface between cone and rubber/foam surround is a significant source of distortion in most drivers....best to get it done right or replace the driver altogether.
For lower end stuff it is cheaper just to replace the entire driver or speaker as the drivers are not worth much and labor is costly.
I would not recommend you go through a third party unless they are approved by Polk. Neither would I recommend you mess with this yourself....the interface between cone and rubber/foam surround is a significant source of distortion in most drivers....best to get it done right or replace the driver altogether.