change existing SharePoint claim provider default claim identifier using powershell

Can we change existing SharePoint claim provider default claim identifier using powershell? We want to modify existing claim from email to samAccountName.

$ap = New-SPTrustedIdentityTokenIssuer -Name "SAML Provider" -Description "SharePoint secured by SAML" -realm $realm -ImportTrustCertificate $cert -ClaimsMappings $map,$map2 -SignInUrl "https://adfsurl/adfs/ls" -IdentifierClaim "http://schemas.xmlsoap.org/ws/2005/05/identity/claims/emailaddress"

Now we want to change IdentifierClaim.

MCTS Sharepoint 2010, MCAD dotnet, MCPDEA, SharePoint Lead