changing light/dark cicle should be sudden or gradually

Hello. My white whidow plant is 2 months old since vegetation phase and she's almost 2 ft height (58 cm) and she has many nodes. I want to put her on flowering phase from 24/24 h light to 12/24 h light and 12/24 h dark. My question is, should i give if the new cicle sudden or should i do this gradually like:

day 1: 23.5 light 0.5 dark
day 2: 23 light 1 dark
day 3: 22.5 light 1.5 dark
day 4: 22 light 2 dark
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day 24: 12 light 12 dark

Thank you,
Cezar

I do sudden and I think most people do also

Ido what arjon from green house does i turn my lighting system off for 72 hour's before this trick's the plant's and they bud much faster go to greenhouse seeds and he will explain better i think its on the ultra haze one.