CREATE procedure [dbo].[MssWebUpdateEmailSignatureDefault]
    @inSysUserId int,
    @inSignatureId int,
    @inDefault bit
as
begin
    update SysuserEmailSignature
    set DefaultFlag =
        case
            when SysUserEmailSignature.SysuserEmailSignatureID = @inSignatureId then @inDefault
            when @inDefault = 1 then 0
            else SysuserEmailSignature.DefaultFlag
        end
    where SysuserEmailSignature.SysuserFID = @inSysUserId
end
GO
GRANT EXECUTE ON  [dbo].[MssWebUpdateEmailSignatureDefault] TO [MssExec]
GO