No problem.
I assume that you have a relationship where one employee has many training events.
On that relationship on the left hand side make a summary field of the maximum of the training date. Call this last training Date.
I assume that you also have training topic as a table and you have a middle many to many table which is the employee training events.
So for example if you were sitting on a training topic record and you were going to add training events and in those training event records you were choosing an employee, you could set the report that is used for the employee drop-down list to be a report of only employees where the training date is more than 14 days ago.
I am kind of guessing at your tables and their relationship so let me know if that does not answer your question. And perhaps better explain your tables and their relationships.