The nodal coordinates are assigned to the pointer np(43) - thus, the easiest way to access them is to include the pointer and arrays as
include 'pointer.h' ! gets np(*)
include 'comblk.h' ! gets hr(*)
then call a routine
call subxxxx(hr(np(43))
where you can then call the array the coordinates
subroutine subxxxx(x)
real*8 x(ndm,numnp)
See programmer manual for how to get ndm and numnp. Now you can access any coordinate you want by node number