Rotate Axis (and not model/objects)

There should be a way to rotate the whole model just using the axis.

I modeled something with animation but facing the wrong direction and I need it rotated 90º but there is no easy way to do that.

If I select all and rotate, it will mess up the animations and other stuff. I just cannot find an easy way to rotate model unless I reanimate everything (and parenting to empties won't work either).

If we could just rotate or move the axis without touching anything in the model it would be much simpler and easy.