Preserving Home and Office Numbers in Emergencies Act of 2021 or the PHONE Act of 2021 This bill restricts the reassignment of a telephone number assigned to a subscriber for the provision of fixed wireline voice service. Specifically, for up to one year after a major disaster has been declared, a number may not be reassigned except at the request of the subscriber. At the request of a subscriber, this prohibition must be extended for an additional year. Further, a subscriber may cancel service without a cancellation fee and resubscribe with the same number and no fee if the subscriber is located in a disaster area and the residence where the number is located is inaccessible or uninhabitable.