Add additional z-values to point cloud

[AntonLarsson]

Is it possible to add extra z-value to a point cloud (las or las-dataset) ? I need to add extra 0,507m to my already existing z-values. I'm changing from a local to an national height system but i don't know the parameters from the local one.

I have tried las2las but i don't know exactly what to do to accomplish what I want.

regards,

Anton