In that case, your only choices would be to 1) Use Interaction Administrator, or 2) Write a custom IceLib interface to allow them to do the same thing, or 3) Come up with a custome front end that allows them to run a handler with the changes you want to make as inputs (users and skills you want to add/remove).
Most people go the other route - they remove skills from the interactions during the peak periods, or they lower the minimum skill requirement in a custom handler.
Removing the skills could be done through a Logical Transfer in Attendant which looks at how many calls are stacked up in queue or the time of day or estimated wait time and branches to a Group Transfer which leaves off the skill requirement when things are backed up. (As an aside, there is a Remove Skill operation in Attendant, but Support does not recommend using it because it leads to faulty reporting data on the queue).