Amending a safe harbor matching formula mid-year

[Guest grazetti]

Can an existing safe harbor match formula be amended mid-year to a different safe harbor match formula? The customer would like to change their basic match - 100% up to 3% of compensation, plus 50% from 3-5% to an enhanced match - 100% of deferrals up to 4% of compensation. Therefore, the new match formula would be increased under the new formula.