Change status field when the ETA date is passed

I have a QB of projects. Have a field called Status (text-multiple choice) with G, Y and R in a list. Green, good.  Red, bad.  Also have an ETA field for when the current stage of the project is expected to be completed.  Is there a way, that if that date passes, the Status field can automatically be changed to R?  To indicate we have a problem?