Example on how to call NSX-T Rest API via powershell to delete a route advertisement rule associated w/ a T1.

delete-routeadvertisementrule.ps1

$NSXMgr=”IPorDNSName”
$Credential = Get-Credential #Must be Enterprise Admin role.  Typically “admin”
$skipcertcheck = $true
$AuthMethod = “Basic”
$TargetRouterName = “LeeroyJenkinsT1”

#To get target logical router id
$lrdata = Invoke-restmethod -Uri “https://$($NSXMgr)/api/v1/logical-routers” -Method GET -Credential $Credential -SkipCertificateCheck:$skipcertcheck -Authentication:$AuthMethod
$routerid = ($lrdata.results | Where-Object {$_.display_name -eq $TargetRouterName}).id

#To get revision number:
$ruledata = Invoke-restmethod -Uri “https://$($NSXMgr)/api/v1/logical-routers/$($routerid)/routing/advertisement/rules” -Method GET -Credential $Credential -SkipCertificateCheck:$skipcertcheck -Authentication:$AuthMethod
$revision = $ruledata._revision

#To clear routing advertisement rules table of target router.
$headers=@{}
$headers.Add("content-type", "application/json")
$headers.Add("x-allow-overwrite", "true")
Invoke-restmethod -Uri “https://$($NSXMgr)/api/v1/logical-routers/$($routerid)/routing/advertisement/rules” -Method PUT -Headers $headers -Credential $Credential -SkipCertificateCheck:$skipcertcheck -Authentication:$AuthMethod  -ContentType 'application/json' -Body (‘{ "_revision": "’ + $Revision + ‘"}’)