Schedule Change - Minimum Turnaround Time

At Sydney, I have several flights arriving at 2210, and others departing at 2340.  This meets the MCT at SYD which is 1:30.

However, due to a curfew at an airport I wanted to add, I have decided to make the entire hub window an hour earlier - arrive at 2110, depart at 2240. 

I have made the schedule change and the flights have been booked.

However, due to unfortunate timing of posting the change, the booked flights have the old schedule on the way in (2210) and the new schedule on the way out (departing at 2240).  This won't meet the required turnaround time for the aircraft (737 - 1:00 at SYD).

Obviously this is a once off, the next day should all be the new times.  Just wondering if I need to cancel any flights?  Will it auto-cancel?  Will they just depart late?  One of the flights is a very profitable long haul flight, so if I know it's not going to work I'd rather cancel and use a transfer flight to at least get one leg in.

Thanks.

The flight will be cancelled, so better better cancel it manually right now to avoid costs.