When an applicant's green card application is approved at or after an interview, they become a Lawful Permanent Resident and would no longer need an Employment Authorization Document (EAD) to work.
However, if an applicant is still waiting for the marriage-based green card interview to happen and they do not have their physical EAD, in general applicants must file a new Form I-765 with U.S. Citizenship and Immigration Services (USCIS) to replace the lost EAD card. There is no fee to do this while a Form I-485 (adjustment of status application) is still pending.
Once Form I-765 application is pending with USCIS for green card applicants, it will automatically extend their work authorization up to 180 days. For more information, please see here.