Help, use Excel to compare two sets of values to keep the duplicates and remove the extraneous value

Riny_van_Eekelen  Thanks for the help, but I'm stuck. I don't know how to do this. I have the values in collum A and B now on the same sheet. They are order numbers. The orders in set A are a list of all order numbers belonging to me. The orders in set B are orders that were billed shipping charges, but they are from a mix of orders that are mine, and orders that are not mine. I need to figure out, using the two tables, which orders are not mine. It is the same situation as I previously described. I am not sure what to plug into xloopup to yield these results. Any help is much appreciated. Thanks