What are some practical ways to resolve legacy code in an n-tier architecture where all of the code is written in self-referencing web services? So far, much of the code is undocumented, uses old VB6 conventions, and there are very long procedures. What's the best way to approach, let's say, a change of business rules for such a large project without having reliable documentation?
I have limited access to the original developer of the code. How can I better document the process and complete my assignments, knowing that the code is changing daily and there are several dependencies for each method, there may be xml files, sql queries, and other unconventional resources being accessed.
Much help appreciated.