Replacing partial customer names in List1 with matching full names from List2...

In list 1, the names are in the order in which customers placed orders, while in the second list, they are in alphabetical order and include full names. I don't have the ability to sort the first list by a criterion, I received them already sorted.
Question: How can I replace each customer name in the first list, where it doesn't have the full name, with the corresponding name from the second list, but keep the order of the names in the first list?