How to change field type in mysql?

Question

MySQL

There is a table with primary id tynyint id is missing.
When you try to change the field to smallint, it swears at errno 150, this is a foreign key error.
I was not going to change the keys at all, or rewrite the id, just the ability to add numbers further is needed.
How to change the field type in this case?

Answer 1

Since this field is used somewhere in other tables as a foreign key, then its type must also be changed there.

Answer 2

a foreign key binds fields of the same type
:
1) delete the key
2) change the type of the field
3) change the type of the associated field
4) create a key