You need a one hour training flight with an instructor on an SEP aeroplane.
If the flight is in a helo, then obviously it doesn't count.
If the instructor isn't an SEP aeroplane instructor, then it's obviously not an instruction flight so doesn't count.
It must be a flight on something that needs the SEP class rating, and must be with someone licenced to instruct on that aircraft, and must be at least one hours duration (two 30 min flights don't count).
One the instructor has signed your log book to evidence the flight, then you need to find an examiner to revalidate the rating.
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