Hello,
1) Execute a dbexport to disk (dbexport -c -o {path to save])
2) cd to the path in step 1.
3) change the name of the directory created {databasename.exp} to {newdatabasename.exp}
4) cd to the new directory created in step 3.
5) open the file {olddatabasename.sql} and change the database name in the header to the new database name.
6) execute a dbimport -c -o {path to directory in step 3}
7) You're done.
Cheers,
Jack