Resize PDF photo for printing

I use Acrobat Pro DC to print out my PDF photo so I can use it for transfering the image to watercolor paper. My PDF is an 8x11, the size of my computer paper. How do I resize the photo so I can use it for watercolor paper that is larger than 8x11? I'm using paper 12x16 now but want to know how to resize a photo in the future for larger paper.