How to change a non root account on multiple esx 4 hosts

We currently use the below script to change the root password but we need one  to change a non root account that does not have access the same way root does.

So if this script could be changed to log into each server with root and then change a non root account's password that would be helpfull.

Any help would be appreciated.

-Steve

#
# This script changes the root password on all ESX hosts in the esxservers.txt textfile
#

# Add VI-toolkit #
Add-PSsnapin VMware.VimAutomation.Core
Initialize-VIToolkitEnvironment.ps1

# Get old root credential
$oldrootPassword = Read-Host "Enter old root password" -AsSecureString
$oldrootCredential = new-object -typename System.Management.Automation.PSCredential -argumentlist "root",$oldrootPassword

# Get new root credential
$newrootPassword = Read-Host "Enter new root password" -AsSecureString
$newrootCredential = new-object -typename System.Management.Automation.PSCredential -argumentlist "root",$newrootPassword
$newrootPassword2 = Read-Host "Retype new root password" -AsSecureString
$newrootCredential2 = new-object -typename System.Management.Automation.PSCredential -argumentlist "root",$newrootPassword2
$WarningPreference = "SilentlyContinue"

# Compare passwords
If ($newrootCredential.GetNetworkCredential().Password -ceq $newrootCredential2.GetNetworkCredential().Password) {

    # Create new root account object
    $rootaccount = New-Object VMware.Vim.HostPosixAccountSpec
    $rootaccount.id = "root"
    $rootaccount.password = $newrootCredential.GetNetworkCredential().Password
    $rootaccount.shellAccess = "/bin/bash"

    # Get list of Host servers from textfile to change root password on
    Get-Content esxservers.txt | %{
        Connect-VIServer $_ -User root -Password $oldrootCredential.GetNetworkCredential().Password -ErrorAction SilentlyContinue -ErrorVariable ConnectError | Out-Null
        If ($ConnectError -ne $Null) {
            Write-Host "ERROR: Failed to connect to ESX server:" $_
        }
        Else {
            $si = Get-View ServiceInstance
            $acctMgr = Get-View -Id $si.content.accountManager
            $acctMgr.UpdateUser($rootaccount)
            Write-Host "Root password successfully changed on" $_
            Disconnect-VIServer -Confirm:$False | Out-Null
        }
    }
}
Else {
Write-Host "ERROR: New root passwords do not match. Exiting..."
}