SEOMa3 - 4:47 am on Jan 30, 2013 (gmt 0)

Have an ecommerce website ABC that is ranking good on SERPs. now, the brand name is changing from ABC to XYZ. All the products will remain the same. only brand name is changing.
Since the domain will also be changing from ABC to XYZ, i do not want to lose out the SEO value i currently have. how can i have a successful transfer from ABC to XYZ without losing my SEO value? XYZ will be going live soon and i need to make sure sure that i start ranking for the keywords which are currently ranking for ABC. both ABC & XYZ are co.uk websites