Can a patent practitioner not of record conduct an interview?
Yes, a registered patent practitioner who is not of record can conduct an interview if they have proper authorization from the applicant. According to MPEP 405:
Interviews may be conducted with a registered practitioner who has proper authority from the applicant, or an attorney or agent of record in the form of a power of attorney or authorization to act in a representative capacity, whether or not the practitioner has a copy of the application file.
The practitioner can show authorization by completing, signing, and filing an Applicant Initiated Interview Request Form (PTOL-413A) or using Form/PTO/SB/84, ‘Authorization to Act in a Representative Capacity’.
Topics:
MPEP 400 - Representative of Applicant or Owner,
MPEP 405 - Interviews With Patent Practitioner Not of Record,
Patent Law,
Patent Procedure