If you cancel your Premium Hosting, your shows will stay intact along with your Profile and show pages.  What you will lose is all of Premium Features including:

No Prime Time (7pm - 11pm ET) Scheduling Restrictions
Host Your Show with Direct Connect and Skype
Private call screening
Dial Out to guests from Studio
Up to 50 Concurrent Live Callers
Extended Show Length Up to 2 hour shows
Upload Podcasts as New Episodes
Edit and Replace Archived Episodes
Priority Support
All Uploaded Audio Clips except for the top 3
Unlimited Content Storage (Limited to 30 hours of content storage)

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