Override Source Build Variable within Provisioner - Possible?

Hello,
I am building a Windows deployment that basically spins up the OS → configures some basic settings → copy the default profile → perform some cleanup.

Issue:
I am using the ‘powershell’ provisioner once the OS is operational to run the ‘copy default profile’ & trying to run the cleanup process. The issue is the provisioner uses the winrm connection specified within the source build. The ‘copy default profile’ run can use those winrm variables. The ‘perform some cleanup’ cannot as I want to remove the account in the original winrm variables. (as well as disable/close Winrm for security reasons)
I could reverse the situation where the source winrm variables point to the permanent account but the ‘copy default profile’ provisioner will need to be overridden.

Question:
Is there a way to specify/override the ‘winrm_username’ & ‘winrm_password’ variaables during the provisioner operations? I see there is an ‘override’ option but looks like it is designed to change the ‘inline’/‘script’ options. Not the communicator connection settings.

Environment:
Packer: v1.7.5
plugin: vsphere v1.0.1
provisioner: powershell

Code:
source - (stripped down)

source "vsphere-iso" "ton_default_win2019_vm" {

  # Builder Configurations
  ## vCenter connection details
  vcenter_server       = var.vm_vcenter_server
  username             = local.vm_vcenter_username
  password             = local.vm_vcenter_user_creds
  insecure_connection  = true
  #
  ## VM location details
  datacenter = var.vm_vdc
  cluster    = var.vm_vdc_cluster
  folder     = var.vm_vdc_folder
  datastore  = var.vm_datastore_build
  #
  ## Packer local HTTP server setup
  http_directory = var.local_http_dir
  http_port_min     = var.packer_local_http_server_port_min
  http_port_max     = var.packer_local_http_server_port_max
  http_bind_address = var.packer_local_http_server_bind_ip
  #
  ## VM ISO boot file
  iso_url         = var.vm_iso_url_boot
  iso_checksum    = var.vm_iso_boot_checksum
  iso_target_path = var.vm_iso_target_path
  #
  ## VMtools ISO & boot drivers
  floppy_files    = var.local_floppy_a_files
  floppy_img_path = var.local_floppy_b_img
  iso_paths       = var.vmtools_iso_path
  #
  ## Boot commands
  boot_wait    = "5s"
  #
  ## VM build details
  vm_name              = var.vm_name
  CPUs                 = var.vm_cpu_count
  RAM                  = var.vm_ram
  RAM_reserve_all      = true
  #
  ## Create Configuration
  disk_controller_type = ["pvscsi"]
  guest_os_type        = var.vm_guest_os_type
  notes                = var.vm_notes
  #
  ## Network Adapter Configuration
  network_adapters {
    network_card = "vmxnet3"
    network      = var.vm_nic1_network_deployment
  }
  #
  ## Storage Configuration
  storage {
    disk_size             = var.vm_disk_0_0_size
    disk_thin_provisioned = true
  }
    ## Wait Configurtion
  ip_wait_timeout = "45m"
  ip_wait_address = var.vm_nic1_ip_address_cidr
  #
  ## Communicator Configuration
  communicator   = "winrm"
  winrm_username = local.vm_winrm_user
  winrm_password = local.vm_winrm_user_creds
  winrm_host     = var.winrm_host
  winrm_port     = "5985"
  winrm_insecure = true
  #
}

build -

build {
  sources = ["source.vsphere-iso.ton_default_win2019_vm"]
  ## Provisioners will run once 'Communicator' has established a connection
  ## Restart target system - release default profile
  provisioner "windows-restart" {}
  #  
  ## Configure WinOS default profile
  provisioner "powershell" {
    elevated_user = local.vm_winrm_user
    elevated_password = local.vm_winrm_creds
    execution_policy = "bypass"
    script = "./env/setup/setup-default-profile.ps1"
  }
  #
  ## Restart target system - release default profile
  provisioner "windows-restart" {}
  #
  ## Perform any post-OS deployment cleanup
  ### This provisioner needs to connect to winrm as different user
  provisioner "powershell" {
    elevated_user = local.vm_winrm_user
    elevated_password = local.vm_winrm_user_creds
    execution_policy = "bypass"
    script = "./env/setup/os-deployment-cleanup.ps1"
  }
  #
  ## Confirmation target system is back up
  provisioner "windows-shell" {
    inline = ["dir c:\\"]
  }
}