PO form chnages

HI Gurus,

can anybody please throw some light on this. When we make a change to hte PO quanity and/or dates we would like for SAP to print all the infomration from thte PO and just not the new line that was added.

For example i create a PO with line 10 and then print the PO. I can see line 10 and its relevant infomrairon. then i go back to the PO and add another line 20 and then save the PO and print it and i see that it only prints line 20 informaiton on the PO. Where do i need to check or what i can do so that no matter what it always printes all the lines

Thanks

anuhsa