Symbol Library - update does not effect docs

[nic]

Hi
Ive made 20 documents and used a macro to place many instances of a particular symbol from a particular csl library into each. I had thought that by updating the symbol in the csl library the documents would automatically be updated but that seems not to be how it works: whist the newly edited symbol will appear in its new form in any new docs the old version of the symbol remains in the old docs.

Is there anyway to get the new version to appear in the old docs without having to recreate the 20 docs already created?
thanks
nic