To reflow an existing jump after text content editing, select Plug-Ins>GN4>Jump>Reflow. Please note that all the jump parts will need their links updated in each of the document pages to enable the ripple effect of edited text to flow backwards/forwards as appropriate.

If a Reflow will cause the text content to fit the current box and therefore a jump part and the continued on text box are no longer necessary, a dialog box will be displayed:

If No or Cancel are selected, the jump part(s) will remain available and the continued on text box will be retained, but if Yes is selected, providing subsequent jumps parts are not already on pages, the jump part(s) will be removed from the Jumps tab listing grid and the continued on text box will be deleted. If the subsequent jump parts are on a page a message dialog will appear (below) and no Reflow will take place.

Have in mind that if you remove jump frames, but you don't save the page, InDesign believes the jumps are still there.