Maybe, but... I've had my husband shorten straight needles, but never a circular. It would be hard to get the join nice and smooth.
But if you have 2 29" needles of the same size (8, or whatever) you could do the two circular needle method. I'm sure you could find a video somewhere, maybe even here on KnittingHelp. Check "Advanced Techniques for one. 2 circulars is not my first choice, but I've done it and it works fine.