Required date for force out

Participant was fully paid out November 2016.  Received match in March of 2016 and Discretionary nonelective in Sept 2017.

Since it is less than $1,000, we need to force out.

Is anyone aware of a date this must be done by?

I don't think there is a hard-fast date like there is for funding deadlines and corrective distributions.  You should have procedures in place to enforce those force out provisions and remain consistent with those procedures.  That may be 4 times per year or 6 times per year.  You'd just want to consistently operate your the plan pursuant to the provisions.

Good Luck!