If you are producing a complex flowchart you will probably
be using some dedicated piece of software, but for simpler examples, you may
well use the drawing tools within Microsoft Office. If you do, then you might
have come across issues with lines staying resolutely static when the objects
they connect are moved:

To complicate matters further, as far back as Office 97,
PowerPoint had 'connectors' which would enable you to connect drawing shapes
with lines that would automatically follow their shapes around. It wasn't until
Office XP that the other applications followed PowerPoint with the inclusion of
connectors for Word and Excel. Although, for connectors to be available in
Word, you needed to create your shapes within a 'Drawing Canvas'. In XP the
drawing canvas used to appear by default when you used a drawing shape (unless
you set the appropriate Word option otherwise).
In Word 2003 and 2007 the
default is not to use a drawing canvas. In Word 2003 you need to go to Insert,
Picture, New drawing to create a canvas, and in Word 2007 the New Drawing
Canvas option is at the bottom of the Shapes dropdown in the Illustrations
group of the Insert ribbon tab. If you create your shapes within a canvas you
should find that, when you choose a connector and 'hover' over a shape, little
blue spots appear around the shape. You can click on a spot to fix your
connector to it, then fix the other end to another shape:
