You can change sequence start values before or after a session by using the following options on the XML Source Qualifier transformation Properties tab:
Reset.
At the end of a session, the Integration Service resets the start values back to the start values for the current session. For example, at the beginning of a session, the start value of a key is 2000. At the end of a session, the current value is 2500. When the session completes, the start value in the repository remains at 2000. You might use this option when you are testing and you want to generate the same key numbers the next time you run a session.
Restart.
At the beginning of a session, the Integration Service restarts the start values using the default value. For example, if the start value for a key is 1005, and you select Restart, the Integration Service changes the start value to 1. You might use this option if the keys are getting large and you will have no duplicate key conflicts if you restart numbering.