I have copied the data from source to destination using below script today.

robocopy \\source \\destination /E /ZB /DCOPY:T /COPYALL /R:1 /SEC /W:1 /V /TEE /LOG:c:\Robocopy.log                                                                                                                                                                                                                                   The copy was successful. However from tomorrow i want to copy only modified files or changed files. What switch i should use. Please help.