So, one of my cousins got married this weekend...and lo-and-behold, his new wife and I both have excellent taste - she wore the exact dress that I own and plan to wear in November. I still love the dress and intend to wear it (who will even remember in a few months, right?) but I would like to alter the gown a little bit to make it just a little bit different.
Here's what I'm wondering. I want to narrow the straps of my dress (remove the "cap" part of the sleeve:

to make it look a little bit more...elegant? Like this dress:

I know that it is more difficult to alter lace, but does anyone with a sewing background know if this is a legitimate possibility? Any other ideas for making my gown a little unique (other than possibly a sash or broach)?
Thanks!