Processes do not substitute for training or else you'll have a 500-pound process document.
An expert may not need detailed subject matter training, but still needs to learn how the process is applied in the organization to ensure consistent execution.
A Final Thought
The observant reader will note I've used a fair number of conditionals as there is no one right way to do this. A fair degree of common sense is needed to be sure you match the breadth and depth of your processes to the business needs of the organization.