What is it that pass from this life to the next?

A friend wanted to know the Buddhist position on rebirth/reincarnation since we don’t believe in a permanent soul. Specifically, what is it that pass from this life to the next? “Karma” was my reply then. There was a look of disappointment; the answer was obviously unsatisfying. I have seen this question asked in this forum in some form or another; here (1) , here (2) , here (3) , here (4) , here (5) , here (6) and there (7) . Looking at the number of times this topic appears, I am not trying to get a definitive answer. Instead, how would you answer this question so that it can enlighten/delight/pacify someone from a non-Buddhist tradition (with some inclinations towards an eternal soul). Note that the target audience do not have a deep understanding in Buddhist concepts e.g. the 5 clinging aggregates. Hopefully, the next time another non-Buddhist friend ask a similar question, I won't turn them off but to **entice** them to investigate further. (Interestingly, looking at the tag info on rebirth in this forum, it says: “The consciousness in the new person is neither identical nor entirely different from that in the deceased but the two form a causal continuum or stream”, I wonder who wrote this.)