Set the initial value of widget in shiny based on the entered value by the user

I need to have an important functionality in my shiny web application. When my application starts, the widgets are with a initial preset value based on what i have programmed in code. Now, the user while using the application will slide the widget, and new values will arise. Now i want a functionality, which would enable the user to start the shiny web application with the initial value of the widgets based on the changed values. This could be done by the user by the presence of some button in my app which would enable the user to determine what the starting value of the widgets in the shiny application would be.