On Windows, the command is: ren *.done *.
On Linux, Reporter provides a utility. In the Blue Coat Reporter folder, this file is called reset.done. Execute this file inside the folder that contains the access logs. If you cannot locate this file, use the following one-line expression.
for i in `ls | grep '\.done$'`; do mv $i `echo $i | sed -e 's/\.done$//g'`; done