help needed to find duplicate names and addresses

i have a issue at work

in the offices they use excel spreadsheets to prints out peoples addresses to deliver things to every day i keep getting the same delivery notes back
even if the delivery notes has been logged as done....

is there anyway we could try and find the same persons name and address by trying to find duplicates or something

i would say the people in our offices are pretty thick as they log the jobs off as been done but continue to print the same name and addresses out maybe 2 days later.......

thanks

Thanks for the title change

Can you upload a small (clean) sample workbook of what you are working with, and what you want.

A few things come to mind (countif and Conditional Formatting for instance) but it may depend on what your data looks like

Another approach might be to use Data Validation, which would prevent duplicate entries, but again, without seeing your layout etc, hard to be more specific