The Laws of Prayer (The morning services) (48)

1. One who is in the middle of praying the Amidah and in the middle of the prayer he has a Halachic question about the prayer which he is in the middle of, (e.g. he forgot to say Ya’aleh Veyavo and is not sure if he should repeat) he is allowed to walk to a place where there is a Halachic book to check. (Shulchan Aruch and Mishne Berurah 103)

2. If he is unable to check for himself, it would appear that he is allowed even to interrupt with speech and ask someone else what the Halacha is. (ibid)