How to use Rename method?

Hello all,

               I have a file in the store file.I used the Metho to get the File.FileNameByName."Having the File name with full path."

a = File.FileByName("abc.txt");

aqfile.Copy("C:\abc.txt");

aqfile.rename(a,"C:\DEF.txt");

at that time Store --> File  abc is n/a inside of Testcomplete Project.