In 2016, General Motors announced a sizable investment of $500 million in Lyft, currently the second-biggest ride-hailing company in the U.S. At the same time, General Motors President Dan Ammann joined Lyft’s board of directors to have a say in the company’s future. That relationship has come to a screeching halt, however.

Bloomberg reported on Wednesday that Ammann has left the Lyft board. He chose Maggie Wilderotter – a former telecommunications executive who sits on Hewlett Packard Enterprise Co.’s board with Ammann – to replace him.

At the time of GM’s $500 million investment, GM and Lyft envisioned a close partnership. GM planned to lease its vehicles to Lyft drivers for short periods of time and also had plans to provide fleets of self-driving cars for Lyft’s network. But Lyft began to stray shortly thereafter.

The ride-hailing company partnered with Ford in 2017 to develop self-driving technology, followed by Google’s Waymo. This past March, Lyft put the final nail in the partnership’s coffin by announcing a major partnership with automotive supplier Magna International Inc.

According to the report, Ammann had to recuse himself from numerous corporate decisions at Lyft following the new partnerships. In addition, GM’s continued focus and investment in its Cruise Automation subsidiary quickly became a point of contention, per an unnamed source.

Despite Ammann’s departure, GM is happy with its investment into the company. Ammann’s departure from Lyft’s board does not impact GM’s $500 million investment, which should come in handy should Lyft decide to go public.