What to do if customer picks up product himself

Someone has ordered a product of mine on amazon and amazon carrier services were supposed to pick up the product an deliver it to the customer but no one from amazon has came to pick it up and they were supposed to come 2 days ago and today it was supposed to be delivered. The customer has contacted me saying he would like to come pick it up himself. I would like to know how will I let amazon know that the customer has picked it up himself as it listed on my account that amazon will deliver it.