Partial update: only the fields you send change, with one exception —
criteria, when sent, replaces every filter, so send the full set of filters you want to keep. category can’t be changed on an existing saved search; delete it and create a new one instead. Changing alertFrequency may also reset schedule, and setting it to NEVER pauses the search the same way pause_saved_searches does.
Returns a results array, one entry per saved search id. Never asks for confirmation.