If you're singing the alto part, whichever section has been given that part, you'd be singing with them, no? Simply line yourself up next to that particular section for that particular song. So, in Docb's example, you'd be a soprano.
You'd still stand with the altos if there were only one song where the director had to do this. And, if you're the only person having this difficulty, this would be a quick fix.
You could always pull a Milli Vanilli for the one song.
The thing about singing any song is not to get locked into how the song is sung on the CD or album and possessing the ability to know the other singing parts as well (with the exception of Baritone/Bass, perhaps ).
I can't really explain it other than to reiterate what I've already said. LOL. I just have an ear and an intuition. And whether I know the song or not, if I can hear the key and the chords, then I can find what
should be my note. If I'm hearing in my head where I should theoretically be, and you're telling me I have to sing below that (the tenor part), it's going to be hard for me to make that stick. And yes, it is MUCH worse if I do know the song and have already registered the original version and parts in my mind. But honestly, even without that, it's still hard for me to sing a tenor part if I'm with the alto section.
Because I used to direct and teach parts, I can always pick out all three (or four) parts in most songs. Even if I've never heard the song, I can easily figure out what the 3 parts are likely to be. But I still have a hard time when they do that. In fact, in the last Praise Team I sang with, we all had a hard time with that, but none of us knew what the problem was until one day I spoke up and then everyone realized that was exactly what they were struggling with. In most songs, sopranos carry the melody. In a few, altos might. It's very odd for the alto to sing two steps below the melody. If the alto was singing the melody in the original, then it's easier to learn it with the voicing changes. But if the soprano sang the melody, and now you've got tenors singing the melody, it's very difficult because altos would be used to harmonizing against the sopranos.
Again, I can't really explain it. I just know it's difficult when you have your ear/intuition telling you what SHOULD BE your part and your director teaching you something different. Fortunately, I don't have to deal with that in my church choir (or at least I haven't had to YET). *crossing my fingers*