Setting OF Change Quantity In Purchase order And Sales Order

Hi All,

in Accounts payable when i want to Change Quantity  in Purchase order Line If Quantity is More ThanPrevious Quantity  , error Occur "Quantity cannot be reduced because the remaining update quantity changes sign"

and in Accountsreceivable when i want to Change Quantity in Sales Order if Quantity is Less ThanPrevious Quantity  , error Occur"Quantity cannot be reduced because the remaining update quantity changes sign"

Does anyoneknows Where i Change or Remove  This Setting IN Dynamics Ax.

thanks all,