Hi,
First check weather the change logs update check box is activated in PROJ table or not.
Path: SE11 > Enter table PROJ > Display > Ctrl+Shift+F9 > Tick "Log data changes"
Then go to SM30 > Enter table PROJ > Ctrl+ F1. That will display all the data change logs in table PROJ.
You can also check tables CDPOS and CDHDR to retrieve change logs.
Thanks