From personal experience I have seen often enough children having disagreements with friends in the classroom. For example: One child has brought a toy from home while another child wants to play with the toy. The child with the toy refuses to share and does not want to play. The other child then becomes upset and they have a disagreement.
How I would manage and resolve this situation of two upset children in the classroom is by lowering my position down to their level so they would feel more comfortable. I would listen to both sides of the disagreement and evaluate the situation before making any decisions. I would then give them time to calm down as children can at times hold grudges and refuse to cooperate. I would then state that toys from outside school premises are not allowed for this very reason. I would then help them find a solution and both take responsibility on their behalf’s. By giving them the confidence to admit there differences and encourage them to feel happy in the classroom again.