NEW YORK (MainStreet) — September is right around the corner and with it another wave of baby boomers who will be transitioning out of their jobs and into retirement, leaving Millennials and Gen X-ers in charge and holding the bag.

"Retiring boomers represent the first generation of professionals and managers to leave the workplace with deep knowledge of complex technical systems, advanced scientific practices and sophisticated management processes," said Dr. David DeLong, author of Lost Knowledge: Confronting the Threat of an Aging Workforce (Oxford University Press, 2004). "This lost knowledge will cost organizations millions of dollars if they don't pay attention to what is walking out the door."

Talking about a strategy is key in helping younger workers to adjust.

"You need to educate and communicate with the staff," said Marc Spector, principal with Spector Group, an architecture and design firm in Woodbury, N.Y. "You can't simply make decisions in a vacuum, or you are setting up yourself for failure. Allow all team members the opportunity to be heard. The CEO can then decide how to proceed with a clear head that everyone had a chance to put their two cents in."

Complicating this on-going adjustment is the fact that many Millennials perceive this shift as an opportunity to make very specific demands.

"They want flexible workspaces and open, collaborative environments rather than private offices and cubicles, which are now predominant," said Scott Spector, principal with Spector Group.

Some 71% of millennials said work demands interfere with their personal lives compared to only 63% of their older colleagues, according to a study by PwC, the University of Southern California and the London Business School.

"Millennials are more interested in a comfortable way of life and as a result choose other priorities such as flexibility in their work and time for other parts of their life outside of work," said Jennifer Mackin, principal, president and CEO with the Oliver Group, a leadership consulting firm.

One way to incorporate the Millennial's collaborative work ethic as hard driving Boomers retire is by encouraging a more relaxed work environment that integrates work and fun.

"We barbecue every Thursday and each member of the firm must be the chef," Scott Spector told MainStreet. "We invite vendors and consultants."

Other perks include half day Fridays during summer months, weekday after-hour mixers and beach parties for family and friends, which can help workers recharge their battery before September starts when they will be picking up the slack for retiring colleagues.

"The key is identifying where the risks of retirements and unwanted turnover pose the greatest threat to future performance," DeLong told MainStreet.

To ease through the transition of retiring co-workers, DeLong advises three things:

1. Ask the retiring employee for his contact info. "This could save a lot of time when you need to reach out with a brief question," said DeLong.

2. Encourage retiring colleagues to share their knowledge well in advance of their retirement date. "If you hear a co-worker talk about retirement, start conversations immediately about how they can transfer what they know before leaving, but be gentle," DeLong said. "Older workers hate feeling like the buzzards are circling. This will increase their reluctance to share what's important."

3. Get connected to the key people your retiring Boomer co-worker knows and relies on. "It is these valuable personal connections that most often get lost when people retire," said DeLong.

--Written by Juliette Fairley for MainStreet