What's the impact of an AD display name change on workflows?

The short answer: None that I can find and I'd like to learn about your experience in the comments section if you saw something different.

My local customer company was bought and now the Active Directory user account display name has to change to match the format of the buying company. The current format is "FirstName LastName" where the first name is followed by a space and then the last name. The new format is to be LastName, FirstName where the last name is followed by a comma, a space, and the first name.

The question put to me was "what's the impact to SharePoint workflows? "

The first thing I wanted to do was create many, many AD user accounts to at least partially mimic what my customer sees on a daily basis. I needed to add about 25K users to AD, so I found and used this "Change UPN" script at https://gallery.technet.microsoft.com/Change-UPN-592177ea. I added more users to the .csv files by opening them in Excel, appending a number to each username, then dragging down while I drank coffee and looked out the window. I ended up with 24K+ new users in this fashion, all set up with the default FirstName LastName display name.

The second thing I had to do was change the display name in my test AD farm to LastName, FirstName without breaking anything. For that, I found this link https://support.microsoft.com/en-us/kb/277717  which describes "How to change the display names of Active Directory users with Active Directory Services Interface script".

Because I only had one AD controller in my test farm, I logged onto it and created a file called c:\temp\chgdisplay.vbs and I edited that file to include the code from the article.

One note I made for myself during testing because I was going back and forth between display name formats was this:

To change from FirstName LastName to LastName, FirstName, use this in the script:   vFullname = vLast + ", " + vFirst

To go the other way, use this:   vFullname = vFirst + " " + vLast

For me and my test environment, the script's "rem Usage" line near the top tells me I need to run the following from a command prompt: cscript chgdisplay.vbs "OU=OriginalUsersTestGroup, DC=brwhite1, DC=lab". Yours will naturally be different, such as cscript chgdisplay.vbs "OU=FinanceUsers, DC=fabrikam, DC=com" .

Below is a screenshot of the chgdisplay.vbs running from a command prompt on its way to changing all user display names in my OriginalUsersTestGroup container in the brwhite1.lab domain.

[caption id="attachment_1035" align="alignnone" width="300"] chgdisplay.vbs in mid-run.[/caption]

The AD properties of Fabrice Canel's account have changed from having display name Fabrice Canel to Canel, Fabrice.

I can't locate the exact online article I used to set up User Profile Services, but you can use this link or find another one: https://blogs.msdn.microsoft.com/russmax/2010/03/20/sharepoint-2010-provisioning-user-profile-synchronization/.

After I ran the user profile sync, I had to log off and back on again to make the old display name go away and see the new display name. You can see below that my efforts were successful. I was able to continue logged in as Fabrice to create new workflow items and I could approve them as the user account with access to manage the workflow items.

I hope you find this useful!