Need help, can't figure out code. Money Transfer Project

Hi, so I'm having trouble with my coding. I've already figured out how to take money from the class values "Tom" and "Rob", but I can't figure out how to deposit that value into the bank. here's what i have so far.
I would really appreciate it if someone would take a look. Each button takes entered amount from related person and transfers it back to the bank which is what i can't figure out.

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace Lab05_E00995877
{
    class Person
    {
        public string Name;
        public decimal Cash;
      
        public decimal ReceiveCash(decimal amount)
        {
            if (amount > 0)
            {
       //      person       money punched in   
                Cash -= amount;
                return Cash;
            }
            else
            {
                MessageBox.Show(amount + "  isnt an amount I'll take",
                    Name + " says..");
                return 0;
            }
        }
    }
}

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace Lab05_E00995877
{
    public partial class Form1 : Form
    {
        //Add your form1 variables
        Person Tom;
        Person Rob;
        decimal bank = 50M;

        public Form1()
        {
            InitializeComponent();
            //Initialize (create) Tom and Rob
            Tom = new Person();
            Tom.Name = "Joe";
            Tom.Cash = 150M;
            btnGetOne.Text = "Get from " + Tom.Name;


            Rob = new Person();
            Rob.Name = "Bob";
            Rob.Cash = 200M;
            btnGetTwo.Text = "Get from " + Rob.Name;

            UpdateForm();
        }

        public void UpdateForm()
        {
            lblFirstName.Text = Tom.Name;
            lblMoneyOne.Text = Tom.Cash.ToString();

            lblSecondName.Text = Rob.Name;
            lblMoneyTwo.Text = Rob.Cash.ToString();

            lblMoneyBank.Text = bank.ToString();
        }

        private void btnGetOne_Click(object sender, EventArgs e)
        {
            decimal decAmount, decTomAmount, decRobAmount, decBankAmount;
            try
            {
                decAmount = Decimal.Parse(txtMoney.Text);
                decTomAmount = Decimal.Parse(lblMoneyOne.Text);
                decRobAmount = Decimal.Parse(lblMoneyTwo.Text);
                decBankAmount = Decimal.Parse(lblMoneyBank.Text);
                //bankamount (bank)   Amount punched in (decAmount)
                if (decTomAmount >= decAmount)
                {
                    decBankAmount -= decAmount;
           
                    lblMoneyOne.Text = Tom.ReceiveCash(decAmount).ToString();
                    lblMoneyBank.Text = bank.ToString();

                    
                     //What do i put here to add to bank after subtracting from Tom?
                    
                    
                    UpdateForm();

                }
                else
                {
                    MessageBox.Show("Tom doesnt have this many!");
                }
                txtMoney.Clear();
                txtMoney.Focus();
            }
            catch
            {
                MessageBox.Show("Please enter numbers only!");
                txtMoney.Clear();
                txtMoney.Focus();
            }
        }
        
        private void btnGetTwo_Click(object sender, EventArgs e)
        {

            decimal decAmount, decTomAmount, decRobAmount;
            try
            {
                decAmount = Decimal.Parse(txtMoney.Text);
                decTomAmount = Decimal.Parse(lblMoneyOne.Text);
                decRobAmount = Decimal.Parse(lblMoneyTwo.Text);
                //bankamount (bank)   Amount punched in (decAmount)
                if (decRobAmount >= decAmount)
                {
                    decRobAmount -= decAmount;
                    lblMoneyTwo.Text = Rob.ReceiveCash(decAmount).ToString();
                    lblMoneyBank.Text = bank.ToString();

                    //What do i put here to add to bank after subtracting from Rob?
                    
                    
                    UpdateForm();

                }
                else
                {
                    MessageBox.Show("Rob doesnt have this many!");
                }
                txtMoney.Clear();
                txtMoney.Focus();
            }
            catch
            {
                MessageBox.Show("Please enter numbers only!");
                txtMoney.Clear();
                txtMoney.Focus();
            }
        }
        }
}