If someone else will be collecting your order, tick the 'Someone else may pick up by order' box during checkout. You will then need to supply the name of the person who will be collecting your order. Once the order has been placed, the alternate pick up person cannot be changed.
When picking up the order in-store, the alternate pickup person will need to supply their photo ID, alongside the collection confirmation email, order number or the name of the customer who placed the order.