When an Adjustment is made to a gift in the Raiser's Edge, you will see the changes in Audit Trail.  This will trigger a change log for the fields that are visible on the Adjustment and will not always show the previous value.  All of the changes will have the same change ID in the far left column and there will be a Gift Type notation of Adjustment.

You can see a sample of this below.

When an Amendment is made, Audit Trail  functions much the same as it does for Adjustments.  You will notice that the Gift Type is listed as an Amendment instead and there are some differences in the fields.