Move is a default rule so you must have altered it yourself.
There isn’t a change entity button by default. You should have select or change entity name ie customer or table.
You can have ml multiple entities on a single ticket is they are different enittiy types. You can only have one for an entity type ie table, so changing table will replace with new table selected.
You could make changing any entity remove any other entity however shouldn’t really need to if setup corectly