From the USPS:
For business customers, temporary modifications continue to be implemented on how mail is handled that must be returned to the delivery office due to a full box or a business not being open to receive delivery for an extended period. Current postal policy during the pandemic is to return the mail to the delivery office and hold it until April 30, 2020. In order to further accommodate businesses during this challenging time, this deadline is now being extended into a longer hold period through May 30, 2020. In addition, there will be a 15-day grace period following May 30, 2020, before mail items are returned to the sender.
Once the business reopens, delivery should immediately resume unless other arrangements have been made. Business customers may request to have their held mail delivered or they can pick it up at their local Post Office. If a business fails to make alternative delivery arrangements or does not submit a request to hold or forward its mail after May 30 and the 15-day grace period, the process of returning mail to the sender will resume.
Business owners with held mail may be contacted by postal management to discuss alternative options.
Assistance will be extended as necessary to businesses who make contact after May 30, 2020, to ensure the cancellation of Moved Left No Address Orders and to immediately resume delivery.