Speaking at the Fortune Most Powerful Summit on Tuesday, executives key to each company’s transformation discussed how to benefit from a long legacy while still embracing disruption. Here are their top tips:

Beth Comstock, vice chair, General Electric (GE): Don’t just add new ideas and businesses. You have to strip away the old, too.

After the financial crisis General Electric added more layers and resources as it focused intensely on the industrial parts of the business. But in “just putting on the new stuff” the company became too slow and cumbersome, said Comstock. As you take on shiny news ideas, don’t ignore what needs to be cut, she added.

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Comstock said that companies should incubate businesses in tandem with customers and startups to move faster, rather than going it alone. It’s easy to fall into the trap of “startup envy” but “certain things are not going to work in our company, and it’s better to partner,” she noted.

Wendy Clark, CEO, DDB North America: Remove anything that slows you down.

“Speed is the equalizer now,” said Clark. To move fast at her ad agency, which she’s run since January, Clark is stressing collaboration. She noted that advertising used to have a reputation of “tiptoeing around people who cannot play well together.” They were given a pass as just being creative. “You can’t meet the speed of the marketplace if you’re trying to protect people’s egos,” she explained.

She said that these principles, such as working together, have been around forever but “business drifted away from that.” She believes that’s changing as women, who represent a collaborative way of working, take on more leadership roles. At DDB she’s trying to foster a team-oriented culture by working with different agencies and embedding clients in their own projects.

She also practices what she calls “discussing the un-discussable.” Tough issues shouldn’t be tackled in the bathroom or hallway after meetings but right at the table, she said.

Julia Steyn, vice president, General Motors (GM) Urban Mobility and Maven: Be intentional about how you structure new operations.

Steyn runs GM’s car sharing service Maven, which is turning the iconic automaker into a service provider rather than a manufacturer. “Cars used to mean freedom and now we need to reinvent what that really looks like,” she said.

Steyn had “trepidations on how to run a startup in a big company” when she took on the role. She wanted to be able to focus specifically on Maven—while still having access to GM’s enormous knowledge base. Steyn focused on walking the line between what “you take from the main organization and what you leverage and pivot and execute in different ways.” To strike that balance, General Motors ended up structuring Maven as a wholly owned subsidiary.