tempdb modify size, move file

Modify the size
ALTER DATABASE tempdb MODIFY FILE ( NAME = tempdev, SIZE = 1024 ).
The database will be resized when the server restarts next.
Move the file
ALTER DATABASE tempdb MODIFY FILE ( NAME = tempdev, FILENAME = 'x:\full\path\xxxx\tempdb\file\tempdb.mdf' /*, SIZE = .... */ ) the file will be created in the new path when the server starts next