Instead of starting at the ChangeSet, you need to begin with the Work Items you want to remove or add to a ChangeSet. In order to remove a Work Item from a ChangeSet, do the following:
- Open the Work Item.
- Change to the All Links tab.
- Remove the link for the ChangeSet of the check in.
- Save the Work Item
You can also add links to other changesets on this tab by choosing "Add New Link" and then selecting ChangeSet as the type of link.