How long before excess calories turns to fat?

...or more specifically, if I eat poorly and exceed my TDEE calories during a single day, can I recover the next day. Meaning can I back off the excess calories (larger deficit) to make up for it or have the excess calories already been converted to fate cells?

Additionally, I have heard over and over that once a fat cell is created it does not get used up, it just gets emptied of all stored contents...as all body cells and parts have a life span and are slowly absorbed or passed as waste, how long does it take for created fat cells to leave the body or be absorbed?