table.ajax.reload(): how do you JSON.parse?

I am trying to reload my table on the click of a button using table.ajax.reload().
I'm getting an invalid JSON error and upon going through troubleshooting with datatables/tn1, I can see that it is returning html/text instead of JSON.
How do I parse the data on reload?
I've tried various ways of combining table.ajax.reload() with JSON.parse(), but none have worked.

Thanks