You mean that long, sustained vocal note?
OK, this is a guess and they may well have done it differently, but to create that kind of effect I'd start with autotune, melodyne or similar on the vocal for the pitch and the vibrato/pitch shifts. Rather than try and minimise the audible artifacts from the process for a natural sound, I'd let it sound artificial.
Compress and/or limit to keep the volume constant. EQ to narrow the bandwidth and harmonics down to focus the sound.
As the vocal begins to lose volume there's what sounds like a resonant filter at the same pitch being brought in. That might be done by filtering the vocal track itself, even as simply as ramping up the Q and gain in any eq that'll resonate. Or clone the vocal track, maybe more than once, and apply the filter to one track and mix it with the "straight" vocal track. Or overlay a synth set to produce a sine or triangle wave.
There's also vocal multi-tracking or doubling going on to add width to the vocal and fatten it up some. Plugins like Waves doubler, choruses and flangers can automate the process, it can also be done by cloning the track a few times and shifting them against each other by a few milliseconds, or applying different vibratos in autotune, or several ways I've probably never thought of. Plus an exciter. Lots of exciter.
And sample manipulation as well I suspect.
It's certainly not impossible that there's a "magic plugin" that creates that sound, but if there is I for one have no idea what it might be. Having said that, it's the kind of thing that's quite possible to do in Sonar or any other DAW and Sonar Platinum certainly has enough tools to do it. It does take quite a lot of work, though it's the kind of thing that probably isn't difficult to do once you've done it a few times, found a formula that works and maybe even saved it out as a track template or pro-channel preset.
Which isn't much help when you've never done it of course.
Learning sound engineering and production is like learning anything else. Before you can run you first have to learn to walk.
If you're not familiar with eq, compressors etc. then I suggest starting with them and not relying on presets but learning about how they work and what the controls do. Someone else's presets aren't much use when you're using lots of effects (but eq and compression in particular) because to get the result they did you'd need to be using the same audio they did and run it through the processing at the same level they did.
For example, a preset to focus an eq on a vocal line won't work if the vocal line you're using isn't at the same pitch as the one used to create the preset. A compressor preset won't work unless the audio you're using is at the same volume as the audio used to create the presets and so on.