Carb refeeds are not supported by research for increasing results on the Keto and are not needed. The premise behind a carb refeed is typically replenishing carbohydrate stores but this is not necessary on Keto since carbs are not the primary fuel source and the body can actually complete this action without the need for carbs.
Certain people may benefit from cycling carbs around their workouts or in the evenings but much more research is needed to support this approach. Keto is not a one size fits all approach. After you are fully Keto adapted and have seen the desired results, you may want to experiment with a dual fuel approach. Meaning you use both carbohydrates and fat effectively for fuel. If you decide to add some carbohydrates into your diet, please do so from whole foods sources, such as starchy vegetables. If you find that you respond with fatigue or other side effects, this approach may not be best for you.