I came across a small type in Section 31.10.1.3. Samba Users. The code in the handbook says to use:

# pdbedit -a username

When using the command above, the results below are displayed:

root@mercury:/home/anthony # pdbedit -a anthony
new password:
retype new password:
Failed to add entry for user .
root@mercury:/home/anthony #

In my experience, the -u flag needs to be added to the command

# pdbedit -a -u username

This way when I run the command, I get a successful result. See below

root@mercury:/home/anthony # pdbedit -a -u anthony
new password:
retype new password:
Unix username:        anthony
NT username:          
Account Flags:        [U          ]
User SID:             S-1-5-21-3825970801-536950418-1120046553-1002
Primary Group SID:    S-1-5-21-3825970801-536950418-1120046553-513
Full Name:            anthony
Home Directory:       \\MERCURY\anthony
HomeDir Drive:        
Logon Script:         
Profile Path:         \\MERCURY\anthony\profile
Domain:               MERCURY
Account desc:         
Workstations:         
Munged dial:          
Logon time:           0
Logoff time:          9223372036854775807 seconds since the Epoch
Kickoff time:         9223372036854775807 seconds since the Epoch
Password last set:    Sat, 08 Apr 2023 22:12:37 EDT
Password can change:  Sat, 08 Apr 2023 22:12:37 EDT
Password must change: never
Last bad password   : 0
Bad password count  : 0
Logon hours         : FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF

For your reference, here is the system I am running the command on

root@mercury:/home/anthony # uname -a
FreeBSD mercury 13.1-RELEASE-p6 FreeBSD 13.1-RELEASE-p6 GENERIC amd