manipulate fields of class

Hello,

let's say I have an object ''CharObj" of Class Character. The class has field Dictionary to keep character values for strength, intelligence, agility (which are fields). Now I want to modify the class (with gui but thats not important) to have field power instead of strenght. Do i need to modify the file Character.cs or can i somehow manipulate the elements of class? via abstract class or interface? example

 public class Character
 {
 int strength;
 int intelligence;
 Dictionary<string, int> abilities;
 }
 
 public class Character2
 {
 int power;
 int intelligence;
 Dictionary<string,int> abilities;
 }
 //
  public class Character : CharacterAbilities
     {
         Dictionary<string, int> abilities;
         public Dictionary<string, int> Abilities{
             get { return abilities; }
             set { abilities = value; } }
         public int Strength {
             get{return abilities["strength"];  }
             set  {  abilities["strength"] = value;  }  }
         public int Agility {
             get  {  return abilities["agility"];   }
             set  {abilities["agility"] = value;  }   }
 }
 
     public interface CharacterAbilities
     {
         int Strength
         {
             get;
             set;
         }
         int Agility
         {
             get;
             set;
         }
 }

if i modify the class file then i will have to modify all the code for initializing objects if i add a new or delete new field in the class, right? Can it be ommited somehow?