Klonopin can remain in your system up to 10 days. As mentioned by the member above, if you have a valid prescription for this medication, you can provide proof of that to your employer before the drug test.
First, I think you meant Klonopin. The elimination half life of clonazepam (Klonopin) is between 20 - 80 hours. Meaning half the drug should be out of your system in this amount of time. The longer you have been taking the drug, and the higher the dose you have been taking, the longer the elimination time will be. The elimination time will also increase if you have impaired liver function. If you have been taking the drug for a long time it is not advisable to just quit. You will need to taper off first. -- Just my opinion now: If you taper for a week then wait another week before your test you probably will be fine. There are some medications that increase the elimination of Klonopin from your system by as much as 30%. I wouldn't recommend this as you might experience withdrawal symptoms. Also, If you have a legitimate prescription for the drug, why not keep taking it and just disclose it at the time of the test. Unless you have already been offered the job and this is part of the pre-employment physical, you are most likely going to have some serious rebound anxiety that wont be helpful in any upcoming interviews.