Having two CHAs is very confusing. We already have someone messaging us by mistake due to it. We had a similar problem when our ticker was CCC and ChocoCoin had it before us. In that case we decided to change it because that was the courteous and right thing to do. In this case, we have been using CHA for a while before ChanceCoin so we will not be making any changes to it.  The ball is on their side of the field.
Cheers