The Image Date and Time Adjustment Tool (Shift+Ctrl+D) can change image creation date and time stored in the EXIF data. It uses selected photographs (or current one if none is selected).
Date and time can be modified by adding specified amount of days/hours/minutes to the current time stamp, or by specifying a new date. Typically relative adjustment is useful to fix time shift due to the time zone changes or daylight saving time change. Absolute specification may be used to establish a new date & time for scanned photographs.
After selecting either relative or absolute time change the tool will immediately preview effects of adjustments. If they look correct pressing OK button will physically modify date and time stored in EXIF block, as well as file time stamp. Please note that this change is permanent and cannot be undone.