You can move occurrences from one room to another. By doing this you will keep all data on the occurrence when you move it. Right click on the occurrence you want to move and select "Move occurrence". If you want to move several occurrences in the same action you can select more occurrences by pressing SHIFT or CTRL.
Note that you cannot move an occurrence that comes from a room template or item template. You can move occurrences to/from unique item lists or additional occurrences in derived item lists.
You can move occurrences to another item list of the same room, only condition is the have the right responsibilities to be able to move an item from one list to the other:
An icone on the top ribbon is a short cut avoiding the click right:
