Fonts & Character Sets ⇒ how to change font as using a lateX class

[nguyennb]

Hi every one!
I am using a lateX class to write a thesis. I cannot change font of the thesis by changing the font argument of the bellow code

Code: Select all

\documentclass[12pt,modernstyle]{thesis}

to

Code: Select all

\documentclass[14pt,modernstyle]{thesis}

How can I solve this problem