As soon as your ball is buried deeply in the sand, there is only one safe way to get it out. You have to steepen your down swing and your angle of attack taking a lot of sand with your club.

The easiest way to do so, is to close the clubface slightly, so that the leading edge of your SW can cut through the sand better when you splash it out with a lot of power.

The trajectory of the ball flight will be not as high as you are used to and there will be also less backspin on the ball, so consider more roll and a shorter landing point for this shot.