Someone may practice blowing shofar on Rosh HaShanah for that day, but not for the next day. By night may one also practice (for that day)?
Answer:
There is no problem in practicing blowing the Shower from night to day. The problem is only from one day of Rosh Hashanah to the next, which is a problem of hachanah. If somebody is only blowing on the second day, he cannot practice on the first night for the second day.
Best wishes.