Resizing Pools
You can resize pools from their bottom and right edges and bottom right corners. Pools must always be at least as large as their contents, including the swimlanes. If you resize a swimlane to be smaller, by dragging its bottom edge upward, the swimlanes below it will resize only as much as their contents are accommodated by their swimlanes.
To resize a pool
1. Select the title bar area of the pool.
2. Click and drag one of the resize handles of the pool to resize it.
Note: If there are steps in the pool, Designer will not allow you to resize the pool to a size at which the steps are not visible.