What happens without bank details
The return is accepted and processed. The IRS mails a letter and then a CP53E notice asking for a response within 30 days, which the taxpayer can give through their IRS Individual Online Account. IRS staff cannot take bank details by phone or in person.
If the taxpayer does not respond and there is no other issue, the refund is released as a paper check after six weeks. Limited exceptions exist for hardship and legal or procedural reasons.