Using the method promoteColumn() does not make any changes to the table structure.
Starting with London release, this method no longer works and has been blacklisted.
The method promoteColumn() is not documented as part of Servicenow documentation and hence we do not support the usage of it.
To promote a field to the parent table you can either:
- create a new field directly on the parent table and use it as an alternative OR
- delete the column from the child table and recreate it in the parent table.