Automation to change energy price at specific date due to new contract

Configuration
1

Hey all,
my first post here. I tried to search for something that helps me there. But I was unable to get an answer. Maybe I just don’t know what to search for exactly.

I want an automation that triggers on 27.03.2023 because thats the date my energy provider changes and my price/kWh changes by alot. My energy price is currently in an helper: input_number.energy_price

alias: Stromanbieter Wechsel
description: ""
trigger:
  - platform: time
    at: input_datetime.stromanbieter_wechsel
condition: []
action:
  - event: New Price
    event_data:
      action:
        - service: input_number.set_value
          data:
            value: 0.35
            entity_id: input_number.energy_price
mode: single