Yes, but this will incur an additional fee and will delay the launch of website. There are some really flexible theme builders out there that allow you to build almost any design with a bit of know how. BUT this most definitely can't be done "in-a-day"!
If you're keen to keep the costs down and get up and running fast, we suggest starting with one of their demo websites / layouts. Then once the website is launched and project completed, you will be able to customise the design to your heart's content.