Oracle Database Discussions

HOW I DELETE A DATAFILE
ADMINISTRATOR GUIDE SAYS THERE'S NO SQL COMMAND TO DELETE A DATAFILE
1. SO U HAVE TO CREATE A TABLESAPCE
2. ADD THAT DATAFILE TO IT
3. DELETE the talespace with option 'including datafiles'

but when i try to add that datafile to a newly cretaed tablespace
i recieve an error says, "the datafiel is part of the database'

thnx for the help