Hi Barry,
We have a setting within the Registration Path Settings that asks how you want to refund registrants if they switch their admission item. You would want to switch this to Amount Based on Refund policy, and then make sure you have a refund policy set in place for the in-person admission item. Within the refund policy, you can setup a cancellation fee to charge anyone who cancels/modifies after a certain date.

This cancellation fee would apply to anyone that cancels or modifies and in-person admission item, not just those that modify.
Hope this helps! Please let me know if you have any questions!
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Madeline Stalnaker [Designation]
Lead Client Success Advisor
Cvent
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