Selection.GoToEditableRange Method (Word)
Returns a Range object that represents an area of a document that can be modified by the specified user or group of users.
expression Required. A variable that represents a Selection object.
Can be either a String that represents the user's e-mail alias (if in the same domain), an e-mail address, or a WdEditorType constant that represents a group of users. If omitted, selects all ranges for which all users have permissions to edit.
You can also use the NextRange property of the Editor object to return the next range for which the user has permission to modify.