Powershell read the output of the process is already running

I have a powershell script which runs an exe and get its output which is working fine, but the issue that i am facing is that if the process is already running then it is not able to capture the output.

Below is my code

$pinfo = New-Object System.Diagnostics.ProcessStartInfo
$pinfo.FileName = "E:\Program Files (x86)\Consul_Ent\Bin\consul.exe"
$pinfo.Arguments = "agent -config-dir E:\Consul_Ent\Configuration\Client"
$pinfo.UseShellExecute = $false
$pinfo.CreateNoWindow = $false
$pinfo.RedirectStandardInput = $true
$pinfo.RedirectStandardOutput = $true
$pinfo.RedirectStandardError = $true
$pinfo.EnvironmentVariables["GOMAXPROCS"] = (Get-WmiObject Win32_Processor | measure -p NumberOfLogicalProcessors -sum).Sum 

$process = New-Object System.Diagnostics.Process
$process.StartInfo = $pinfo
[Void]$process.Start()
$process.BeginOutputReadLine()
$process.BeginErrorReadLine()

try
{
    while (!$process.WaitForExit(1))
    {
    }
    Write-Host "WaitForExit(1)"
}
finally
{
   # give the thread gracefully shutdown
   Start-Sleep -s 3

}

so as the process is not terminated yet and hence it is not able to read the output as it tries to create a new instance, i want it to create a new instance only if process is not running but if it is running i just want to capture the output.