The flame may become low if the candle has burned for more hours than normal. Wax that has formed on the sides melts and reduces the length of the exposed wick. If the flame is too low, and there is melted wax in the pool under the flame, blow out the candle carefully, pour out a small amount of wax and relight. While doing this, carefully expose more of the wick by digging out a little wax around the wick. This should allow the candle to be relit.