nightmare....please help

I’m facing a big issue since one week

can you help for this particular issue

 the deal is the following :

i should check in folder favourites under contacts in outlook if user toto has reviewer permission ;

if so do nothing

 if not add or modify existing permissions as reviewer

i do this with ews api but this cause me the issue that deleting all other existing users permission after folder.update() is applied

you have an idea to deal with this issue ? part of my code that update the folder (currently delete the user and add again the rights

############################################################################################################################## if($existingperm -ne $null)

{ output("Removing existing permission to toto on Contacts\Favourites")

$removal = $favouritesFolder.Permissions.Remove($existingperm)

output("Removed existing permission to toto on Contacts\Favourites") }

$newfp = new-object Microsoft.Exchange.WebServices.Data.FolderPermission("toto@toto.com",$ReviewerPermission) $favouritesFolder.Permissions.Add($newfp) $favouritesFolder.Update()

output("Granted Reviewer permission to toto on Contacts\Favourites") }