Before assignment:
Open the Learning Path from Learning Paths → [path name] → Edit. You can typically change the name, description, add/remove courses, reorder items and update the skills or due dates.
After assignment:
You can still edit the Learning Path, but be aware: edits made after assignment will affect reports (they change what is reported for that assignment) but they do not retroactively change a learner’s existing course progress (completed modules remain completed).