How can I make my duplicate values null?

[KonaCantTalk]

I was looking throughout the community thinking this was already asked, maybe it has been and I just couldnt find it, but I was curious to know if there was a way to make duplicate values show as null. 

For example, lets say I have customer ID numbers as follows: 

Customer ID #

12345

45832

78043

92378

72213

12345

I would like to have one of these customer ID numbers switched to null. Not the whole row of data just the one cell, or Customer ID #.

Thank you! 

[KonaCantTalk]

I will accept this as the solution since it works for the sample data set you provided. It didnt work for my data set though. I re-checked the steps and I mirrored what you did but it just changes my Customer ID column to 1, 2, 3, etc. to match. Not sure what I did wrong, I will try to look for other ways to do this.

[AndrewS]

Happy to assist if you want to post a sample of your actual dataset. It's probably just pointing the duplicate and formula tools to the right field/s.

[KonaCantTalk]

I did look over your 2nd workflow from yesterday, thanks for commenting again. You rock @AndrewS! That worked perfectly! I now have my Customer ID column with only unique values and the duplicates are null! Exactly what I needed. Thanks again!