In Picking Sheet Printing (off the Sales Order Main Menu); there is a Select Button on the top right of the screen.,  That allows a user to "re-select" any Pick Sheet for sales order numbers, listed in the select field grid, on the bottom of the screen.  By default that area is "all sales orders".  It is really easy to click that button and re-select all picking sheets for re-printing. 

Thank you for the reply Stefanou. Actually my problem is that the PickingSheetPrinted field in the SalesOrderHeader table doesn't get updated from "N" to "Y" after picking sheet gets printed. Though this doesn't happen to all orders, it does happen on a few orders which I feel really strange...have you seen anything like this before? Is it a system glitch or data corruption?

Thank you for the time.

Is the sales order for Drop Ship Items?  A Picking Sheet won't print for a Drop Ship Item. 

No. they are normal orders with regular items. The picking sheets did print as I got paper version and kept in folder. However the PickingSheetPrinted field in the SalesOrderHeader table doesn't get updated from "N" to "Y".

The only things I can think of is that you have a SO printing form code that looks like a picking sheet (something we do often), or the picking sheet was printed from a test / copy company code.

The only things I can think of is that you have a SO printing form code that looks like a picking sheet (something we do often), or the picking sheet was printed from a test / copy company code.