This is probably very simple but I always find a way to over complicate things.

1. I need to identify the latest instance of each header Id, in the example below I want to update the Last_Instance field to say 'yes' based on the most recent 'Last_Update_Da te', in this case 11/2/07 12:02 AM.

2. I need to update the 'From_Date' to be 'Last_Update_Da te' of the previous instance. See examples below.

This...