I would check with the maker to be sure ... but I believe you can change to a higher voltage - but not a lower.
I would tend to agree with John, here.
If the manufacturer doesn't know, no-one does.
In these days of multi-voltage equipment (ie: made to run all over the world), you'd think that this sort of thing would be reasonably happy with any within say 100-300VAC, I could be way wrong though.
