Use Dialog to configure the save as dialog before the action fires. For example, you can set the save as dialog's default extension at design time using the Object Inspector. Dialog is also useful for reading the selected file name from an OnAccept event handler. 

When using a file save as action, you do not place a TSaveDialog component on the form or data module at design time. Instead, you add the TFileSaveAs to your action list and then use the Dialog property. The save dialog component is created by the TFileSaveAs constructor. 

OnAccept 

OnCancel