There are 2 parts to a USDA FSIS NR answer - 1) what was done to fix the issue (Corrective Measure) & 2) what was done to prevent a recurrence.
You have an answer to 1): you fixed the Flow Chart (FC) & Hazard Analysis
For 2), what ideas can the HACCP Team come up with: a) someone verifies changes to the HACCP plan for accuracy before the changes are implemented; b) the HACCP team will periodically walk the floor checking the FC steps against what is actually happening on the floor; c) was rework discussed elsewhere in supporting documentation, but that step was accidentally not transferred to the the FC, etc. a & b are standard actions that should already be happening.
Rework is a basic consideration for any HACCP/HARPC plan - how was it missed? How long has it been missing? An Internet search will turn up multiple documents that list the big chunks that should be in any HACCP plan. The training documentation for the HACCP trained person on the team should also have this info.So you could say the the HACCP Team reviewed one/some of these documents against your HACCP plan to ensure that all applicable steps are now present.
Fix any other issues now before USDA FSIS Inspection finds something else.
Keith