To set a new origin and recalculate all feature locations, select the position you want the new origin to be at, right-click to open the contextual menu and choose the option Set Origin.

Note that only circular sequence can have their origin changed. To change the circularity of a sequence, acces the sequence properties by either selecting the entire sequence (Ctrl-A) or select the sequence node in the Explorer window (keyboard shorcut Ctrt+Shift+1), and cgange the value of circularity in the Properties Window.