Differential rows

I am using SSIS to replicate data from an AS400 mainframe to a SQL destination. I am using a lookup column to see if the primary key is duplicated and if not, it will INSERT the row. This is all working fine. What I need to know is can I also use the Lookup transformation to look for differential data and then UPDATE the row? The primary key of the table will never change, however the data might and I need the package to recognize that this is a modified row on the mainframe and that the same row on the SQL destination server needs to be updated.

Thanks for any useful information.

I believe that I found a solution to my own problem. It looks like I need to use the Slowly Changing Dimension transformation. So far in running the test data, this is exactly what I need.