If it's a nicer model watch, they don't always need a punch. The band may have "adjusting links" on one end only -- normally near the clasp. Screws might be holding those links in. You can only remove the links that have screws, not the ones held in by pins, if that's how it's made.
Also, check the clasp. Some have a few holes for the band's spring-loaded pin to click into. You can "micro-adjust" the band size by selecting different sets of holes to attach the band to the clasp.
If you're removing links, make sure to put them somewhere you'll never lose them, like a safe or safe deposit box. One day, you'll need them, and it might be years down the road when finding matching links is almost impossible.