A — Approach
C — Communications
C — Cooperation
E — Employees
P — Processes
T — Tools
The key specifics are in the article [1]. I just don't want to copy paste it here.
And yes, despite being easily applicable to any other discipline, ACCEPT is a mandatory part of BRSE.
In application of ACCEPT to BRSE, the letter "A" stands for BRSE itself.
At the moment, it just outlines management areas of focus and commitment without any other specific guidance: you pick each BRSE function and break your management work into ACCEPT areas which you populate with own tasks and measure the progress.