What form should I use to petition for acceptance of a late maintenance fee payment?

If you need to petition for acceptance of a late maintenance fee payment, you should use Form PTO/SB/66. According to MPEP 2595:

“Form PTO/SB/66 (“Petition to Accept Unintentionally Delayed Payment of Maintenance Fee in an Expired Patent ( 37 CFR 1.378(b) )”) may be used to file a petition under 37 CFR 1.378(b).”

This form is specifically designed for situations where a patent has expired due to unintentional failure to pay a maintenance fee. It allows patent holders to request reinstatement of their patent rights under 37 CFR 1.378(b).

To learn more:

• late maintenance fee
• petition
• expired patent
• reinstatement