You can't. You have to provide a SELECT statement, and you cannot directly SELECT from a stored procedure's results. You can replace the stored procedure with a user-defined function - either an inline table-valued function, which simply contains a single SELECT statement, or a multistatement table-valued function. Alternatively, the INSERT statement can insert the results of a stored procedure into a table (e.g. INSERT table (columns) EXECUTE stored_proc). You would need to create a temporary table or table variable to store the results, with the appropriate schema, insert into the temporary table/table variable, then declare the cursor to select from that.
Stability. What an interesting concept. -- Chris Maunder