So far I've seen ALTER TABLE RENAME, ALTER TABLE CHANGE and ALTER TABLE MODIFY.

What I'm trying to achieve is something like ALTER TABLE my_table RENAME col_old_name TO col_new_name, which can be a case of modifying a column.

SQLite goes with RENAME.
MariaDB and MySQL have all three.
Postgres goes with RENAME.
Oracle has RENAME and MODIFY.
Standards are unkown to SQL Server.

What is the database-agnostic way for renaming (or generally altering) a column?

So far I've seen ALTER TABLE RENAME, ALTER TABLE CHANGE and ALTER TABLE MODIFY.

What I'm trying to achieve is something like ALTER TABLE my_table RENAME col_old_name TO col_new_name, which can be a case of modifying a column.

SQLite goes with RENAME.
MariaDB and MySQL have all three.
Postgres goes with RENAME.
Oracle has RENAME and MODIFY.
Standards are unkown to SQL Server.

What is the database-agnostic way for renaming (or generally altering) a column?

Maybe I'm erroneously expecting the standard to cover DDL operations as well? I have code that works with multiple databases so would rather make the SQL part as portable as possible.