The GM handles day-to-day operations like managing the cap, call-ups and roster decisions, etc. The are also the middleman between players, agents, the coach, and other GMs. They negotiate contracts and trades.
The President is above the GM, they are in charge of both hockey operations and business operations. The only person they answer to is the owner. The actual involvement each President has in daily operations vary. Some just give the long term vision and trust the GM to execute it and really only exercising veto power. Some might give specific instructions, like “extend this player” or “trade for this guy” and the GM follows suit. Some take the lead in hockey ops and will be much more hands-on. Some will act as the middleman to ownership and have to “sell” their ideas before getting permission for their GM to act.
With our ownership, it’s kind of tough to tell what this move will mean. This may just be a vote of confidence in Fitzgerald, giving him job security and a raise. Maybe he’ll be transitioning more to the business side with Marty, Madigan, etc handling the roster stuff. I guess we’ll find out a bit more at the press conference later today.