Tribal Worldwide, Amsterdam has appointed Sandra Krstic to succeed Jacco ter Schegget as agency's co-CEO. Ms. Krstic, who will run Tribal Worldwide, Amsterdam, alongside co-CEO Ivo Roefs, was appointed deputy managing director a year ago. She will continue to manage global clients including Heineken, TomTom and Adidas.

David & Goliath has appointed Chip Waters as associate creative director. Waters will report to David Angelo, founder and chief creative officer of the L.A.-based agency, and Colin Jeffery, executive creative director and managing partner. His primary client focus will include Kia and California Lottery. Prior to D&G, Mr. Waters spent six years as a copywriter at Venables Bell & Partners, where he helped Audi launch its TDI series in America. He also helped create a campaign for The Meth Project directed by Darren Aronofsky. More recently, Mr. Waters was a copywriter at twofifteenmccann, where he worked on creative campaigns for Xbox and Hewlett Packard.

Adam&eve/DDB London has promoted Alex Hesz to director of digital as part of a management shakeup. Mr. Hesz, formerly managing partner, will run a digital division whose clients include Google, YouTube and Lipton globally. He recently appointed a new head of social, Simon Adamson, who joins this week from 1000 Heads. The agency has also promoted former managing partners Tammy Einav and Mat Goff to the new positions of joint managing directors while former DDB managing partner Xavier Rees is promoted to group managing director of London.

Philadelphia agency Red Tettemer O'Connell & Partners has made several new creative appointments. Megan Auld-Wright joins as a copywriter, having worked in a similar role at design firm Ultra, while Chris Arasin joins as interactive designer from FourFront. Alex Moreno and Joe Schoppy join as junior social creatives, while Meg Dibley joins as junior producer from Wonderful Machine where she worked in a similar role.

Omelet, a Los Angeles-based branding, marketing, and entertainment company, has promoted Sarah Anderson to chief creative officer. Ms. Anderson, who has been serving as partner and executive creative director, will continue to oversee creative for clients including AT&T, Coca-Cola, Microsoft, Moët & Chandon, and Whole Foods Market.