How can I add my ride today to my training plan

I am currently following a Century Plan, finishing week 12 out of 22 - I was due to due 2 hrs in zone 2 today. I rode indoors and followed a course on my Edge 830 but this is sitting as a separate ride from that due in the Plan. Is there any way the workout/ride I did today can be added to the plan? Otherwise my training status is adversly affected...'first world problem' I know but...