Need to design a web based application in a configurable way.

Hi, Need an web based application in a configurable way.  Currently, I'm developing a HR Compensation application, which will be delivered to number of clients. My Problem is, each and every client asked a customized change in that application, where it affects the workflow also. Consider a client asked to add one field, like a checkbox if i checked that one it will go to another new workflow, that is submitted to Next level officer. After that higher level officer approval, then only it will go next stage. Some of the clients doesnot need these function. My idea, is it possible to change the ENTIRE application as a dynamically configurable based on fields as well as workflow. Give me your good suggestions. My application using Web Forms & ASP.Net 4. Thanks!
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