The Study date is a DICOM field that is set on the Imaging device and is not a LifeSys editable field. It is part of the medical record and cannot and should not be altered on the PACS.
The only way to fix this is set the correct time and settings on the modality/device. Once the date and time settings are properly set-up, study can be deleted and then re-send to LifeSys.
To know more about Study date and other system timestamps, you may logged in the system and visit the Decision Support link