Expanding Seamless

Is there an easy way to expand seamless? I got a great shot but a good section of the background is off the seamless and there's a lot of business in the background.

Photoshop's Content-Aware Scale does an OK job. Depends on how much of a gradient you have in the lighting on the seamless, and how much extra space you have.

If the subjects are too big for the backdrop paper, the problem becomes much, much more difficult than if you just need to hide background clutter.

Run the paper horizontally & clone the seam if you have to add a 2nd layer on the floor.