I assume you mean you can't make the width shorter.
If you can't drag the right edge of the report towards the left you
probably have a control (usually a line) extending to the current
right position. It can be just at the extreme top or bottom of a
section which means it is going to be hard to see in Design View.
Use the Object drop-down control to highlight each line in turn until
you find the culprit. Reposition it or make it shorter, then drag the
right edge to the wanted size.
