If you want the sample materials are sent to the sales office and that it should be taken back once the exhibition is over. Better you go with consignment fillup process where, you treat the sales office as a sold to party and the exhibition venue as ship to party. Of course, you will have to take care of ED and VAT part.

With this settings, the inventory will only get reduced from manufacturing plant and will be in sales office account as "Cust.consignment".

Once the exhibition is over, you can create a consignment pick up and take back the exhibition materials to the manufacturing plant.

VLMOVE will not meet this requirement. VLMOVE - will be useful for goods movements for handling units and materials with 23 options inside it.

For material there are 17 options and none of the options suits your requirement.

This TCode will not be useful If you want to use this transaction for sending exhibition materials to your sales office.