How do I make socks smaller?

[kristalstjean]

I am knitting my mom a pair of socks for Christmas. I am using a pattern, and the size says "women's small" but clearly it's not small enough. Without starting over, how can I "shrink" them? I was thinking of somehow adding tight elastic to make them stay up..are there any other ways or recommendations? ( I know about changing guage and all that..im asking about ways I can alter the socks when they are made).