Thule rack crosspiece?

how do i take off the strap so i can attach it to the sidebars? like the crosspiece not the actuall snowboard rack http://www.thule.com/en/US/Products/Snow鈥?/a>|||The feet of the Thule rack should un bolt. If you can't do that how will you tighten it back on the cross bar to hold it in place? If you lost the wrench contact Thule to get a new one.