PredicateRewriter.cs

static class  PredicateRewriter
        {
            public static Expression<Predicate<T>> Rewrite<T>(Expression<Predicate<T>> exp
, string newParamName)
            {
                var param = Expression.Parameter(exp.Parameters[0].Type, newParamName);
                var newExpression = new PredicateRewriterVisitor(param).Visit(exp);

                return (Expression<Predicate<T>>)newExpression;
            }

            private class PredicateRewriterVisitor : ExpressionVisitor
            {
                private readonly ParameterExpression _parameterExpression;

                public PredicateRewriterVisitor(ParameterExpression parameterExpression)
                {
                    _parameterExpression = parameterExpression;
                }

                protected override Expression VisitParameter(ParameterExpression node)
                {
                    return _parameterExpression;
                }
            }
        }