Create a pagesetup in a template and use psetupin.
I use this to import my page setups.
(defun c:page (/ f)
(vlax-for x (vla-get-plotconfigurations (vla-get-activedocument (vlax-get-acad-object)))
(vla-delete x)
)
(setvar 'filedia 0)
(cond ((setq f (findfile "X:/Path/pagesetups.dwt"))
(vl-cmdf ".-psetupin" f "*")
(princ "\n <<<Pagesetups Imported>>>")
)
((princ "\n <<<Pagesetups NOT FOUND!>>>"))
)
(setvar 'filedia 1)
(princ)
)