Ok, figured it out,
On the put away worksheet is a function called change unit of measure, this is used to change the UOM up (Units to Pallets) as it is being put away, this is also available on the movement card
The process to change the UOM up while an item is in a bin is to create a movement where the source bin and destination bin is the same, then use the function to convert the UOM, this will take it out in the old UOM and put it back in the new UOM
Cheers
Nev