As we have explained, there is an uncertainty regarding a garment on which the sides were folded but not sewn down. Preferably, one should avoid wearing such a garment. If one had no choice but to wear this folded garment, he should follow the view of the Shulchon Aruch. If a garment is so long that it cannot be worn unless it is folded, the poskim disagree about whether it is required to have tzitzis. Practically, if one must wear this garment, he should place the tzitzis on the original corners and wear it without a brocha.
[שו"ע י, ו, משנ"ב טז ו־יט, ושעה"צ כז]