Bulk edit of 1 million records and WCF client application

Scenario: My application is in client server model. The server hosts a set of WCF services to serve the data to the WCF client applications. One of the database tables has 1 million records. For that table, I have to provide a bulk edit feature at the client side.
The tricky requirements here is

- Customer wants to perform multiple edits/inserts before actually saving the data back to server. At the same he wants to undo the changes.

- All other client applications will get an alert to refresh their screens through a WCF callbacks whenever data got changed in the server. The alert should go after user completes the bulk edit operation. During the edit, other clients should not get an alert.
Environment: WCF services self hosted in a XP machine, all client applications gets data through WCF service.
Problem:

1. Getting all 1 million records to client through a dataset does not seem to be a good solution.

2. On each edit, I don't want to update the server database table, because that will trigger a alert to other clients

3. User wants to perform UNDO (up to many levels) whenever he wants.
What will be the best approach? Any suggestions!? Thanks in advance.