DH died in the summer after a long illness.
I've been making an effort to get out and a about in recent weeks and have met up with people I haven't seen since before he was ill (mostly due to covid).
Some are old friends, some are more acquaintances. Most know he was ill, some know he died, but I haven't seen them since he died for them to offer face to face condolences.
So, the first thing that happens when we meet is they tell me how sorry they are and I say something ridiculous like "that's OK" or "these things happen" 
What's the correct way to acknowledge what they've said and move the conversation on quickly?