You can convert an existing Dynamic Web project into a Client Services Web project by using the Convert Project to Client Services project wizard. This retains the existing web application logic of the project, and will add Client Services tooling support.
There is no wizard to convert a Client Services Web project back to a Dynamic Web Project. If you wish to retain the original Dynamic Web Project, you must copy the project before converting it. This can be done by selecting the Copy project before conversion
check box in the wizard.
Parent topic: Creating Web Application projects: XPD622