When you edit a port name in a transformation, by default, the Designer propagates references to that port in the expressions, conditions, and other ports in that transformation. You can also propagate changed attributes throughout the mapping.
The Designer propagates ports, expressions, and conditions based on the following factors:
The direction that you propagate.
You can propagate changes forward, backward, or in both directions.
The attributes you choose to propagate.
You can propagate port name, datatype, precision, scale, and description.
The type of dependencies.
You can propagate changes to dependencies along a link path or to implicit dependencies within a transformation.