Hi krishdm,
Thank you for reaching out to Microsoft Community.
I'm sorry but RAM is integrated on the board of the Surface Book and there is no option or workaround for us to add RAM on it.
If this answer your question, we highly encourage you to inform our Community by clicking on Yes or marking my post as an answer. This will help other members who may have the same issue as you. Otherwise, don't hesitate to update us so we can further assist you.
Kind Regards,
Marrion Y.