Read news from a db - Pentaho Kettle.

Hi, I'm job with pentaho and I have a question:

How to "read news" from a table to database?
For example I copy a table "A" from the database "1" to table "B" from database "2" with transformations 'Input Table' and 'Ouput Table'. But I insert a new record or update record in table "A", so through pentaho read the changes and update table "B".

It is understood?

Thanks