You can use the AppUnload method of the IIsWebVirtualDir object to unload a Web application that is running out-of-process. All of the application's resources are released and the application's process is terminated. If the application is running in-process, the application is released if it is not being referenced by any other applications.
IIsWebVirtualDir.AppUnload
<%
Dim VDirObj
Set VDirObj = GetObject("IIS://LocalHost/W3SVC/1/ROOT/MyAppVDir")
' Unload the application at this directory
VDirObj.AppUnload
%>
AppCreate, AppDelete, AppDeleteRecursive, AppUnloadRecursive, AppGetStatus, AppDisable, AppDisableRecursive, AppEnable, AppEnableRecursive