You can edit an animation curve that is referenced into a parent scene. These edits can include adding, deleting, and moving keyframes as well as changing tangent types.
To edit referenced animation curves
When this preference is on, you can edit referenced curves in the same ways you edit any other curve. (When off, referenced animation curves display as dotted lines to indicate they are non-editable.)
As you edit referenced curves (for example adding, moving, or deleting keys, changing tangents and tangent types), all edits are stored in the file's reference node and can be exported to an .editMB or .editMA reference edits file. The file can then be assigned to another scene to propagate the reference edits. See Export reference edits to an offline file and Assign reference edits to an offline file.
To open the Reference Edits window, -click the reference node in the Outliner and select Reference > List Edits. See Remove reference edits.
As you modify referenced animation curves in the Graph Editor, you can also compare the referenced curve and the result animation using the Buffer Curve options.
To view or swap the referenced and result animation while editing reference curves
This takes a snapshot of the referenced curve and displays it in the graph view area.