When working with an Equation object in MS Word 2007 or newer, is there a way to force a line break inside the equation?

Using Shift Enter causes a line break, but it also breaks the equation, i.e. then I have two equations instead of one. It seems that some operations (alignments) still operate on them as a unit, whereas the operation of converting from display formula to inline formula treats them as separate equations. I wonder whether this is serious.