May be there are more efficient ways of doing this, but I could only found following procedure:
1) Create a new DB
createdb -U db_user new_db_name
2) Dump data from original DB
pg_dump -U db_user -Fc original_db_name > dump_file_name
3) Restore to new db
pg_restore -U db_user -d new_db_name dump_file_name