Forum Post: Workflow created

I want to create a workflow for my organization ,workflow details are below :-

I want to shoot a mail to HOD , when case is escalated for more than 3 days,i want to know how can i put a check on the date.

for e.g. if i create a case on 1st April and case is still not resolved  within 3 DAYS  then mail is shoot to the HOD .