Change ondelete behavior on SQL table

I have previously done:

ALTER TABLE `cms__model__file_taggable_tag` ADD CONSTRAINT 
cms__model__file_taggable_tag_id_cms__model__file_id FOREIGN KEY (id) REFERENCES 
cms__model__file (id), ADD CONSTRAINT 
cms_开发者_Python百科_model__file_taggable_tag_tag_id_taggable_tag_id FOREIGN KEY (tag_id) 
REFERENCES taggable_tag (id) ON DELETE CASCADE ON UPDATE CASCADE; 

but I meant to execute (forgot to add on update cascade constraint):

ALTER TABLE `cms__model__file_taggable_tag` ADD CONSTRAINT 
cms__model__file_taggable_tag_id_cms__model__file_id FOREIGN KEY (id) REFERENCES 
cms__model__file (id) ON DELETE CASCADE ON UPDATE CASCADE, ADD CONSTRAINT 
cms__model__file_taggable_tag_tag_id_taggable_tag_id FOREIGN KEY (tag_id) 
REFERENCES taggable_tag (id) ON DELETE CASCADE ON UPDATE CASCADE; 

How can I remove the previous constraints and apply the correct one?

Tried:

ALTER TABLE `cms__model__file_taggable_tag` DROP CONSTRAINT 
cms__model__file_taggable_tag_id_cms__model__file_id

got:

#1064 - You have an error in your SQL syntax; check the manual that corresponds
to your MySQL server version for the right syntax to use near 'CONSTRAINT 
cms__model__file_taggable_tag_id_cms__model__file_id' at line 1

Use SHOW CREATE TABLE tableName to check if MySQL has actually created the constraint and if it has changed (truncated) its name.

Then use DROP FOREIGN KEY, not DROP CONSTRAINT:

ALTER TABLE cms__model__file_taggable_tag
  DROP FOREIGN KEY cms__model__file_taggable_tag_id_cms__model__file_id

Check the MySQL docs: ALTER TABLE and FOREIGN KEY Constraints

First,

ALTER TABLE tablename DROP CONSTRAINT constraintname

Then, put your corrected constraints back in.

Edit: Didn't notice you were using MySQL. I believe MySQL's syntax is

ALTER TABLE tablename DROP INDEX indexname

Replace the word ADD with DROP in your ALTER clause