Q. Last year it happened to us that we did not have at hand any olive oil when we prepared the menorah for lighting and therefore placed wax candles instead. Then, right before lighting, we received some olive oil. Was it correct to remove the wax candles and use the olive oil?
A. As mentioned in prior question (2446), dedicating or preparing an item for use in a mitzva, does not usually create any restrictions since “hazmana” in regard to mitzvos is not effective (Rema O.H. 638: 1, regarding a suka that was not used).
Horav Shlomo Miller’s Shlit’a opinion is that he may change the wax candles to olive oil. However, if he already began the brocho, even if he did not mention Hashem’s name, he should continue.
Aruch Hashulchan (673: 6) maintains a similar opinion.
Rabbi A. Bartfeld as advised by Horav Shlomo Miller Shlit’a