I noticed [concrete observation]. Is everything ok?
I noticed [concrete observation] happened a few times now. What’s the pattern here?
[non-personal topic] has been on my mind. Could we have a quick chat to figure it out?
May we spend a bit of time going through your progress on [initiative]?
Do you have a few minutes to dive into [initiative] with me?
Holding people accountable and being held accountable do not seem like fun until you consider the alternatives (which are really bad). Do yourself and others a favor and learn how to do this.