Is there a way to change the header font to san serif?

[Daisuke Koya]

Hello all,

I am using LyX 2.0.4 on Mac OS 10.7.4.

I am using the "fancy" headings style to display headings (LyX: Document 
Settings >> Page Layout >> Headings style).

I'd like to know whether the header font can be changed from the default serif 
font to a san-serif one.
Is this possible, and if so how is it done?

I thank you all kindly.

Best regards,

Daisuke