Ms. Thaler, 46, is leaving Wells Rich at a sensitive time.
Ms. Heller said it took a long time before deciding to leave Wells Rich.
Wells Rich has been on shaky ground with Benson & Hedges for several years.
Over the years Wells Rich has gone to great lengths to keep the high-profile account.
Wells, Rich has billings of about $800 million.
Hard as it tried, Wells, Rich could not stem the slide.
A spokeswoman for Wells Rich declined comment, but said that billings were $6 million.
Wells Rich will create branding ads to build awareness for the company's telecommunications services.
Wells Rich, which has had the corporate account for 16 years, continues to handle Ford accounts like its electronics and credit units.