If the booking was made on Booking.com, it needs to be amended on Booking.com as well.
Any changes we would be making in SuperControl would not be filtering back to Booking.com and amend the booking there.
The next time the data is forwarded from Booking.com all changes made in SuperControl would be overwritten.
Please note:
Booking.com does not check the availability for a property before moving a booking.
This means the booking will be moved by Booking.com regardless, if the dates are available or not.
Alas, this could result in you receiving a double booking due to no fault of your own, but you will still need to be dealing with the communication to the guests, explaining what has happened.