Is there actually 8 TB of data in the database? If so, then even shrinking can't help you, that's the legitimate size of the database. Though you could look into Data Compression for your largest tables to help minimize the space they consume on disk.
The answer will depend on how the tablespace being enlarged is defined. At a minimum you will need to drop the first tablespace to free up space on your storage (see here for syntax):
drop tablespace old_tablespace [including contents and datafiles];
If the datafiles in the tablespace marked for growth were defined with AUTOEXTEND and still have room to ...