Kohl's is wonderful about returns... they will take anything back with tags on at anytime. Now - if you don't have the receipt, you will get the last rpice in their system, which if the item had been clearanced might be very low - and this happened to someone on the Disboards a couple of years ago, she had a purchased some shoes, and two years later decided to return the unworn shoes. She did not have a receipt, so the store told her the value they could return them was at $2.00. The poster was LIVID.
Now - if she would have had the receipt, it just wouldn't have been a problem to get her purchase price back.
I shop at Kohl's often, as I live in the area where the chain started, so there are lots of them around. I purchased a bra in the wrong size (way wrong...I must have grabbed the wrong one - DUH!) I returned it about 8 months later, with the receipt. It took me so long, because I kept forgetting to actually do this task.
Your best bet, with any store, is to have the receipt, and the OP does. They may ask the reason for the return, tell them you've changed your mind. There just won't be a problem.