I'd like to pull the ground away from one of my basement walls to create a "walkout" condition. I'm assuming the current base of the foundation and footing in that area will no longer be below frostline, it will be at the frost area fulltime. How does this get handled? Does a new foundation wall have to go in front of the existing wall, and then go down the 4' to create a new below frostline condition, at least in the front area of the newly exposed wall? Is this a complicated process, and what type of contractor would have the best practices for this problem? Thanks

You'll needd to check with your local building department, a foundation contractor and probably a structural engineer. In some places, it's allowed to bore 12-16 inch wide holes at various locations under the footing and pour concrete pillars to support the footing, basically making the above frost line footing into a grade beam and structural loads are transferred to the pillars. Just an idea of what they may tell you.

Build4you is generally correct in describing what must be done. It is a form of underpinning. The size and spacing of the concrete pillars will depend on the loads coming down on the footings (one-story?, two-story?, bearing wall?, roof load also?) AND your soil type and bearing capacity, and the presence, if any, of a water table near the footing bottoms.