Hi @vinaykl,
You would need to define the two parameters in the code.
Their declaration can be found in clock_S32K1xx.h

You can use the CLOCK_DRV_GetSystemClockSource() and pass the defined struct there first to get the current clock source. Then change it and use it in CLOCK_DRV_SetSystemClock().
However, the SDK 3.0.0 Processor Expert allows creating more clock configurations.

The system clock can be updated using CLOCK_SYS_UpdateConfiguration().
Regards,
Daniel