Hi, if I sold my chometz with a Rabbi (I wrote down my name on a piece of paper with many other names but I didn’t fill out any actual contract) but I did not explicitly say that “I hereby appoint him as my agent to sell the chometz” – rather, he said he is my shliach and I said something like thank you or nodded my head (I don’t recall exactly) – is that fine? Or do I need to say it explicitly out loud (and if I need to, can I still say it out loud later to myself)? Thank you.
It is better to say it specifically, but this way is also good, as it is understrood that this is what you mean. It is clear that the Rabbi was selling the chometz for you, otherwise what were you doing?