Can you gave me a fix in my code

I'm trying to build my C# project, I get the error: The modifier 'abstract' is not valid for this item Is the item: FieldChanged; In the following Interface:

namespace program.Drawing.Fields
{
using System;
using System.Collections.Generic;
using System.Runtime.CompilerServices;

public interface IFieldHolder
{

abstract event FieldChangedEventHandler FieldChanged;

void AddField(Field field);
Field GetField(FieldType fieldType);
List GetFields();
bool HasField(FieldType fieldType);
void RemoveField(Field field);
void SetFieldValue(FieldType fieldType, object value);
}
}