Int 21 Fn 4A  - DOS 2+ - Resize Memory Block                               [D]

   AH = 4Ah
   BX = new size in paragraphs
   ES = segment of block to resize

Return: CF clear if successful
   CF set on error
       AX = error code (07h,08h,09h) (see AH=59h)
       BX = maximum paragraphs available for specified memory block

Notes: under DOS 2.1-6.0, if there is insufficient memory to expand the block
     as much as requested, the block will be made as large as possible
   DOS 2.1-6.0 coalesces any free blocks immediately following the block
     to be resized

See Also: AH=48h,AH=49h,AH=83h