If you are talking about the EC in your nutrient mix then simply dilute it down with more water.
If you are talking about getting the EV down in your run off out of your pot, there are two ways to do this. 1) Start feeding a lower EC solution and feed enough to have 20% run off. This will flush out your excess nutrients in the soil while still feeding your plant. 2) Water with straight pH balanced water at a rate of 1 gallon per gallon of your container. This will flush any salt build up in your soil. (This is usually only done if you are experiencing issues with your plant)
I usually only use the first option when I see my EC start to creep up in my run off.
I hope this helps.