Blu-ray disc release dates can and sometimes do change multiple times, but the home video company typically provides new release date information when a change occurs. In some cases, release date information isn't available, although this typically isn't the case when release date changes occur.
If a customer preorders a Blu-ray disc and the release date changes, the retailer may notify the customer, although this depends on the retailer. The retailer usually doesn't charge the customer until it ships the Blu-ray disc. If there is a price change between the time the customer placed the preorder and the Blu-ray disc's release date, the customer receives the lower price. Preorders are typically available weeks or months before the release date.