I'm not certain that I clearly understand your problem, but let me say this:
Once a Profile is entered and saved, you should be able to make the changes you want from that Profile's edit tab. (near the top of the Profile). You can enter or edit the formal name, preferred name, nickname, etc - and any of these can be represented by an initial. BUT REMEMBER to SAVE your changes (click on the "save changes" button) BEFORE leaving that page.
Hope this helps.