Intonation adjustment on a uke?

Is there much that can be done? I just picked up an Ohana concert uke (dont have the model number on me), and now that the strings have had a chance to stretch, it has become increasingly obvious that notes go noticeably flat past the tenth fret (flat, not sharp, go figure). I definitely do want to use the very highest frets, but I have no idea if the instrument's intonation can be improved, as it doesn't have a truss rod. So should I just exchange it for a better set up instrument, or would a competent tech be able to fix it? I suspect that nothing can be done, but I figured I may as well ask around, right? Thanks!

Yes good question!
I Also had this on my mind. There are some modifications to the saddle or action and many other things.
Like Ryan said that Jake altered Aldrines uke..

Q: What are possible modifications that we can do to our ukulele?? If so, how?

What kind of strings do you have on, and how long have you had them?
Actually, doesn't matter.

If it goes flat after your strings are settled, change the strings.

bump bump bump?