I just had a urn built for my motherinlaw out of oak but it is an inch and 3/4 to tall what would be the best way to cut it down without damage is octogon in shape ...?
I thought bandsaw ?
Without seeing it, a bandsaw would be my guess. You might just take it back to whoever made it for you and ask them to cut it down.
Sight unseen I'd say a band saw. If it wobbles make some kind of sled for it to slide on.