Why does FDisk's Editor Close when Running the Command 'a'?

I hope this message finds you well.  I am writing because I ran the following in my OpenBSD device and am uncertain why it stops running:

virtual-server# fdisk -e sd1 
Enter 'help' for information
sd1: 1> a
virtual-server#

I thought a was the shortcut for add but perhaps I am mistaken. Did this command do anything? Or perhaps it crashed?