Take a look at the section on Editing Connecting Lines in VCF (GMTOOTMG, page 238+) as that will give you an idea of the issues involved. There may be a case for a separate VCF Primer that talks about the do's and don'ts in chart construction. I have not tried to compose one as it could quickly became out of date if some of the quirks were adjusted in an update or there was a major version upgrade. (I have a list of about 150 reported quirks and requests for enhancements but I have no idea when or if there will be a change in status of any of them.)
It would be better for you to describe the operation that you are trying to do and for some of us to describe how we would approach it. Because VCF editing can be very flexible there are usually several ways to achieve an outcome. Secondly, some sequences are more prone to user error than others, so the sequence of operations is important to get the desired result in the minimum number of steps.
I perform hundreds of these editing operations on the reshaped (compacted) charts that I create on an almost daily basis. HINT: As a general rule, it is better to copy then paste then edit the pasted object than creating an object from the tool bar - the toolbar objects can't always be edited to have the same propertis as the ones already on the chart!