如果您还指定了更多参数，则可以在多种格式上使用ParseExact：

# .Net expects a strongly typed string array

# (must implement [System.Collections.IEnumerable]), so cast to [string[]]

[string[]]$formats = 'MM/dd/yyyy HH:mm:ss', 'MM/dd/yyyy HH:mm'
Import-Csv -Path 'D:\Test\theTimes.csv' | ForEach-Object {
    $date = [datetime]::ParseExact($_.Time, $formats, [cultureInfo]::InvariantCulture, 'None').ToString('dd\/MM\/yyyy H:mm:ss')
    [PsCustomObject]@{
        Time = $date
        Incident = $_.Incident
    }
}

对于您的示例数据，这将产生

Time                Incident   
----                --------   
25/03/2021 12:59:49 INC18072411
03/04/2021 13:00:00 INC17989469
14/05/2021 13:01:57 INC17987450
28/05/2021 13:02:56 INC18000995
01/06/2021 13:06:00 INC17990104
06/06/2021 13:06:23 INC17983804
19/07/2021 13:07:00 INC17973858
08/08/2021 13:08:04 INC17987287
20/09/2021 13:08:19 INC17986031
10/10/2021 13:13:00 INC17926602

使用regex，您可以在将输入字符串解析为[DateTime]类型之前添加缺少的秒数。

$InputData = @'
Time,Incident
03/25/2021 12:59:49,INC18072411
04/03/2021 13:00,INC17989469
05/14/2021 13:01:57,INC17987450
05/28/2021 13:02:56,INC18000995
06/01/2021 13:06,INC17990104
06/06/2021 13:06:23,INC17983804
07/19/2021 13:07,INC17973858
08/08/2021 13:08:04,INC17987287
09/20/2021 13:08:19,INC17986031
10/10/2021 13:13,INC17926602
'@ |
ConvertFrom-Csv

$InputData |
ForEach-Object {
    $TimeString = $_.Time -replace '(\d{2}\/\d{2}\/\d{4}\s+\d{2}:\d{2})$', '$1:00'
    [PSCustomObject]@{
        Name     = ([datetime]::ParseExact($TimeString, "MM/dd/yyyy HH:mm:ss", $null)).ToString('dd/MM/yyyy H:mm:ss')
        Incident = $_.Incident
    }
}