If you want to recreate your temp tablespace, then follow below steps. For changing the default tablespace also, below steps can be used.

Find the existing temp tablespace details

SQL> ;        
  1* select tablespace_name,file_name from dba_temp_files
SQL> /

TABLESPACE_NAME 	       FILE_NAME
------------------------------ --------------------------------------------------------
TEMP			       /home/oracle/app/oracle/oradata/cdb1/orcl/orcl_temp01201
			       4-07-30_04-39-23-PM.dbf

Create another Temporary Tablespace TEMP1

CREATE TEMPORARY TABLESPACE TEMP1 TEMPFILE  ‘/u01/app/oradata/DBACLASS/temp01′ SIZE 2G;

Move Default Database temp tablespace

ALTER DATABASE DEFAULT TEMPORARY TABLESPACE TEMP1;

If any sessions are using temp space, then kill them.

SELECT b.tablespace,b.segfile#,b.segblk#,b.blocks,a.sid,a.serial#,
a.username,a.osuser, a.status
FROM v$session a,v$sort_usage b
WHERE a.saddr = b.session_addr;

ALTER SYSTEM KILL SESSION 'SID,SERIAL#' IMMEDIATE; 

Drop the original temp tablespace.

Drop temp tablespace

DROP TABLESPACE temp INCLUDING CONTENTS AND DATAFILES;

If you want to change the name from TEMP1 to TEMP, then follow the same process as below.

Create TEMP tablespace

CREATE TEMPORARY TABLESPACE TEMP TEMPFILE /u01/app/temp/temp01′ SIZE 2000M;

Make TEMP as default tablespace

ALTER DATABASE DEFAULT TEMPORARY TABLESPACE temp;

Drop temporary for tablespace temp1

DROP TABLESPACE temp1 INCLUDING CONTENTS AND DATAFILES;