change column to nullable

hello,
could someone help me out with some code to change a column from not nullable to nullable in a sproc? i need to do this temporarily and then change it back.
thanks!Refer to Books online for ALTER TABLE... ALTER COLUMN topics.|||i have checked BOL... i was just a little confused.

is this the correct way for an already existing column?

ALTER TABLE MyTable ALTER COLUMN myColumn int NULL

then to change it back...

ALTER TABLE MyTable ALTER COLUMN myColumn int NOT NULL