As they level up in the Day Care, Pokémon will not undergo evolution.
So, when you take it out of the Day Care, it won't evolve. However, in order to evolve it, you'll just need to level it up to the next level and it will evolve.
Since you don't know how Level Up Evolution works, I will accept to explain it to you. Let's take Magikarp for example. Magikarp can evolve from Level 20 onwards. This means when Magikarp reaches Level 20, it will evolve. If you cancel the Evolution process (keeping Magikarp as Magikarp), Magikarp will attempt to evolve when it reaches Level 21, so on, so forth until it reaches Level 100 since you are in Gen 3.