A modest drop in demand for Saudi crude, which means they sell a bit less at their posted prices.

Not sure what, if anything, makes them change price at this point.

Supply shocks that could cause demand for their output to fall further include a resumption of output from Iran, an increase from Iraq where development was going full tilt last I checked, and a bit from continued output increases and falling consumption in the US.

On the other hand, if Iran shuts down completely the call on Saudi output could spike beyond their ability to increase production and they’d lose control of prices on the upside.