Here is a simple Delphi procedure that takes a file name and a date/time as its two input parameters, and sets the date and time the file was last modified (i.e., last write/modification date/time stamp) to the input date/time. For additional Delphi code for the Windows operating system, see Useful Delphi Code for the Windows Operating System.

procedure SetFileLastWriteDateTime(FileName: String; DateTime: TDateTime);
begin
     If (FileName <> '') and (FileExists(FileName) = True) then
        begin
             TFile.SetLastWriteTime(FileName, DateTime);
             //TFile record is found in the IOUtils unit
        end;
end;