Rescan or Reprocess People in Lightroom CC

[RomFro]

For the People feature, is there a way to force it to rescan or reprocess for faces in a photo or group of photos in LRCC?

For example, if you accidentally tell it to ignore a person but later want to tag the person, it stops giving you that person as someone without a tag. I also have instances where there is a person in the photo, and it just does not recognize them as a person, so it does not ask you to label them.  

Is there was a manual way of making these adjustments?

[selondon]

As I recall, re-sorting happens within 24 hours.

Has the option to tag the ignored face re-appeared? Or can you see a box around it in the Keyword panel?