Modify column type

Is there a way to modify the type of an existing column?  All I actually
want to do is extend the length of the type from a VARCHAR(6) to
VARCHAR(100).

        Column         |         Type          |       Modifiers
------------------------+-----------------------+------------------------email                  | character varying(6)
|not null
 


gold_program=> ALTER TABLE student MODIFY email varchar(100);
ERROR:  parser: parse error at or near "modify"