Amendment after year end to increase deduction

[Jakyasar]

Hi

It has been many moons since I have done one of these under ... drawing blank

Given that amendments now can be adopted after year, if I want to increase deduction for 2023 and sign the amendment by 3/15/2024 (2 1/2 months), could it be just an amendment or still an election needs to be made under ... drawing blank (I think it 412c3 or something like that)

Thanks

[Jakyasar]

Addendum, under 412d2, phew