I'm facing the same question fretje faced in this question, but the answer on that thread was a one-off for his specific problem.
Is there a general case solution to making elbow connectors with multiple elbows in PowerPoint 2007?
How to add a ‘multiple elbows’ to an ‘elbow arrow connector’ in Powerpoint 2007
microsoft-powerpoint
Best Answer
YGA may want to do what I have been trying to do, that is:
Add additional "elbows" to an existing elbow connector in order to fine tune the layout of the connector. For example, to make the connector go around some other object rather than through it (which might be the effect powerpoint automatically applies). The only solutions I have found so far is to fake powerpoint out by inserting other objects and/or rotating objects to cause the effect to be applied by powerpoint automatically, then removing any extra objects. Clumsy.