It does have that ability on the HomePod minis that I have around the house. If a timer is set on one of them and then I want to reset it or add minutes to it,

It does have that ability on the HomePod minis that I have around the house. If a timer is set on one of them and then I want to reset it or add minutes to it, I can do so (but only when that HomePod mini hears me).