To add: This is the event logs you will see at Windows 2012 R2 if the code was successful in changing the username password

you can filter it by this numbers in Windows Security event logs search for: 4662,4723,4724,627,628,4771,4738

4662 - An operation was performed on an object

4723 - An attempt was made to change an account's password

4724 - An attempt was made to reset an accounts password

627 - Change Password Attempt

628 - User Account password set

4771 - Kerberos pre-authentication failed

4738 - A user account was changed

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Log Name: Security
Source: Microsoft Windows Security
Event ID: 4738
Keywords: Audit Success
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user account was changed.

Subject:
    Security ID:        devfsmendoza\useradmin
    Account Name:        useradmin
    Account Domain:        devfsmendoza
    Logon ID:        0x65F62

Target Account:
    Security ID:        devfsmendoza\user1
    Account Name:        user1
    Account Domain:        devfsmendoza

Changed Attributes:
    SAM Account Name:    -
    Display Name:        -
    User Principal Name:    -
    Home Directory:        -
    Home Drive:        -
    Script Path:        -
    Profile Path:        -
    User Workstations:    -
    Password Last Set:    24/2/2017 1:55:09 PM
    Account Expires:        -
    Primary Group ID:    -
    AllowedToDelegateTo:    -
    Old UAC Value:        -
    New UAC Value:        -
    User Account Control:    -
    User Parameters:    -
    SID History:        -
    Logon Hours:        -

Additional Information:
    Privileges:        -
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