The website does indicate "can be retuned to other keys;" but they give no indication (that I found) of what is a permissible range of retuning. Possibly they're suggesting just "sharping" or "flatting" individual strings, and keeping the same overall range, rather than shifting the whole range as one does commonly with some other instruments (e.g. lap dulcimers).

The price listed for a set of strings is quite reasonable, at $35, but implies fairly "simple" stringing, which may not allow the flexibility in "adjusting" string weights some of us are accustomed to with other instruments.

John