Int 1A Fn 0D  - Time - Reset Rtc Date/time Activated Power-on Mode (ibm)   [B]

   AH = 0Dh

Return: CF clear if successful
   CF set on error
Desc:  cancel a previously-set power-on alarm

Note:  IBM classifies this function as optional

See Also: AH=07h,AH=0Ch,AH=0Eh