Protocols, seems to be the standards and norms of the office and how to address and work with each person in the West Wing, this was a tough one to chase down. But I did find a rare New York Time article that mentions President Trump changing protocol...
By then, the president, for whom chains of command and policy minutiae rarely meant much, was demanding that Mr. Priebus begin to put in effect a much more conventional White House protocol that had been taken for granted in previous administrations: From now on, Mr. Trump would be looped in on the drafting of executive orders much earlier in the process.
Another change will be a new set of checks on the previously unfettered power enjoyed by Mr. Bannon and the White House policy director, Stephen Miller, who oversees the implementation of the orders and who received the brunt of the internal and public criticism for the rollout of the travel ban.
So it appears to be some internal set of rules for how policy gets made, and not really law.
But if I were to wager a guess, it would be that there are certain ways in which staff addresses the president.
Here's a example from Huffpost on a meeting former president Obama and there is indeed a fair bit of protocol.
If you have the chance to meet President Obama, will you know what to say? If you want to send him a letter, do you know how to address the envelope? Here are some tips on how to behave if you’re ever lucky enough to meet the highest-ranking official in the United States.
• People who are seated should rise when the president enters the room.
• The president should be addressed as President Obama or Mr. President. (One day in the future, when we have a female president, she will be addressed as Madame President).
• All U.S. presidents retain their title for life, so all former presidents are referred to as Mr. President or President [last name].
• A letter to the president should be addressed as follows:
The White House
1600 Pennsylvania Avenue NW
Washington, DC 20500
• The salutation of your letter should read: The Honorable Barack Obama, President of the United States, or President Barack Obama.
I would imagine, similar guidelines exist for staff and executive staff. I bolded one rule which I would wager is a MUST for any staffer, regardless of position (executive or not) that the must all follow.