Feedback without labels
A useful conversation describes behaviour rather than assigning a personality.
Stay with what happened
Words such as careless or difficult compress a whole person into a judgement. Describe the observable event, the context and its effect instead. This creates something both people can examine without first agreeing on a label.
Leave room for another view
The manager may not have the complete explanation. Ask what the other person noticed and listen before deciding what the situation means. A feedback conversation needs enough structure to remain clear and enough openness to learn something.
Agree the next action
End with a specific expectation and the support needed to meet it. Check that both people understand the agreement and when it will be revisited. Feedback becomes useful through what changes after the conversation.