Ambassador, a Seattle startup, has added former leaders of Zipwhip to its team to fuel growth.Ambassador helps brands acquire customers through conversational commerce software by offering customer referral and rewards programs.The company has over 200 customers, including Verizon, H&R Block, and Kaplan, with an annual recurring revenue of around $3 million.Investors backing Ambassador include former leaders of Zipwhip, which was acquired by Twilio for $850 million.