Q&A: Sale of Foreign Rights and Self-Publishing?

I received a question in my inbox the other day for which I know not the answer  to and was unable to find the answer, so I thought I would ask you guys if you knew.

“My question pertains to the sale of foreign rights and self publishing. I’ve sold rights to a foreign publisher, but how does self publishing my second book affect my prior sale and future foreign rights sales?”

Any answers for a fellow writer?