A question (or two) about 'builds'

For someone who's as experienced as I'm supposed to be, I really feel as though I should already know the answer to this question. But the fact remains that I don't. I've discreetly asked the one other person I know who plays CoH in person. He didn't know. I've tried looking it up in the help sections and in the CoHwiki. So I've done my due diligence. My questions concern the concept of 'build' and are as follows.

What's the difference between a 'respec' and a 'build'?
Can one character share two builds?
Could I have my 'Billy Batson' type alt change into Captain Marvel with a new build?
How does one go about initiating a different build?
Or is this whole build thing a casual reference to destroying your alt and redoing it altogether?

Please forgive my squirrely ignorance. But I figure the only way to learn, is to ask.

1.) A "build" refers to the powers you have chosen and the slots you have assigned to those powers. A "respec" is when you make changes to a build.

2.) Each character can have up to 3 different builds (the second is available at level 10, the third at level 50 after running Mender Ramiel's arc).

3.) Sounds like what you want is to switch costumes more than switching builds.

4.) You have to talk with a trainer in order to switch builds.

5.) Deleting a character and redoing it altogether (perhaps as a different AT or with different powersets) is called "rerolling".

http://paragonwiki.com/wiki/Multiple_Builds

http://paragonwiki.com/wiki/Power_Respecification

Just a couple of quick expansions on the answers you already have:

Quote:

Originally Posted by Bruthaman Could I have my 'Billy Batson' type alt change into Captain Marvel with a new build?

IT depends. You can change the look, as mentioned with teh reference to costumes. But with a different build you cannot change your Fire/Fire blaster into a Cold/Thorn Dominator, nor into an Energy/Psi blaster. You can take different powers and in a different order, but you cannot change your Archetype, origin, primary or secondary power set.

You are free to ditch or select new power pools (have one build that flies and one with no travel power for example). And you can take different Epic and Patron pools.

Quote:

How does one go about initiating a different build?

While it is true that you talk to a trainer, specifically there is an option to "select or rename character build". That's what you want. Before you swap to your second build, give your current one a name. Once you have changed you cannot change back for 10 minutes, so name the build first, then swap over.

All builds start at level 1 with no powers or slots selected. You have to level up one step at a time, but do not need to regain the experience all over again.

First off, to Young Tutor and Gavin Runeblade, let me say thanks for your replies.
I am not so much interested in a cosmetic costume change (which I already know about, thank you very much) as I am in the specific example I mentioned.
Anyone who remembers the original Captain Marvel (which admittedly was a long time ago) will remember that Billy Batson was a child somewhere between twelve and fifteen, whose alter ego was the adult Captain Marvel.
I have a schoolgirl, Laurie Kinnison, who will I guess, grow up to be a sonic Blaster called Screamin' Mimi. I guess what I'm really asking is whether or not one can adjust the physical sliders in a 'build'? So that one could be a child of immature stature and the other be an adult. Because although there certainly have been a lot of changes made in my extended absence, stature changes wern't being offered in respecs before I went away.

Ah and HA!
The Science Booster Pack you say. This sounds like just the ticket!
Mille Graci!