$token = ""
$base64AuthInfo = [Convert]::ToBase64String([Text.Encoding]::ASCII.GetBytes(("{0}:{1}" -f "azdo",$token)))

$uri = "https://dev.azure.com/{organisation}/{teamproject}/_apis/wit/wiql?api-version=5.1"

$body = @"
{
    "query": "Select [System.Id], [System.Title], [System.State] From WorkItems 
    Where [System.TeamProject] = {teamproject} AND [System.WorkItemType] <> 'Test Case' 
    asof '2020-01-08T10:00:00.000Z'"}
"@

$result = Invoke-RestMethod -Uri $uri -Method Post -ContentType "application/json" -Headers @{Authorization=("Basic {0}" -f $base64AuthInfo)} -Body $body

foreach ($result in $result.workItems)
{
    $uriWorkItem = "https://dev.azure.com/{organisation}/{teamproject}/_apis/wit/workitems/" + $result.id + "?asOf=2020-01-08T10:00:00.000Z&api-version=5.1"
    $workitem = Invoke-RestMethod -Uri $uriWorkItem -Method Get -ContentType "application/json" -Headers @{Authorization=("Basic {0}" -f $base64AuthInfo)}

    $oldValue = $workitem.fields.'System.IterationPath'
    $newValue = ($oldValue -replace "{OldTeamProjectName}", "{NewTeamProjectName}") -replace "\\", "\\"

    Write-Host $oldValue -ForegroundColor DarkRed
    Write-Host $newValue -ForegroundColor DarkGreen

    if ($newValue -ne "{NewTeamProjectName}")
    {
        $uriWorkItemUpdate = "https://dev.azure.com/{organisation}/{teamproject}/_apis/wit/workitems/" + $result.id + "?api-version=5.1"
        $update = @"
[
        {
    "op": "add",
    "path": "/fields/System.IterationPath",
    "value": "$newValue" }]
"@

        Invoke-RestMethod -Uri $uriWorkItemUpdate -Method Patch -ContentType "application/json-patch+json" -Headers @{Authorization=("Basic {0}" -f $base64AuthInfo)} -Body $update
    }
}