Well, that's only a portion of an INREC, OUTREC or OUTFIL control statement. There would be a p,m before CHANGE giving the starting position and length of the input field and possibly a c: before that to indicate the output field position (or the output field position could be set by default). But let's assume the input field position and output field position are the same for simplicity. In that case: The portion you show changes a X'0881991C' value in that field to a X'0000000C' value, and changes any other value in that field to a X'9999999C' value. So basically it's changing P'881991' to P'0' and any other PD value to P'9999999'.
For some more information on DFSORT's CHANGE parameter, see: