Graceful ways to break away from a conversation
It usually depends on the situation. If it was a company telling me about a product I might be interested in, and I hear them out, I usually end with 谢谢,我再考虑考虑

if it's one of my my friends, I usually make an excuse such as have to go now, have to sleep, have to eat etc... and add something like 我们哪天接着聊吧, or 回头见

If talking to my parents, I usually say 就这件事, or 没有别的事, etc