diff --git a/contracts/ReferralRegistry.sol b/contracts/ReferralRegistry.sol
index 2db7f75..32a8666 100644
--- a/contracts/ReferralRegistry.sol
+++ b/contracts/ReferralRegistry.sol
@@ -57,6 +57,9 @@ contract ReferralRegistry is UUPSHelper {
     /// @notice Mapping to store user to referrer relationships
     mapping(string => mapping(address => address)) public keyToUserToReferrer;
 
+    /// @notice Mapping to list referred
+    mapping(string => mapping(address => address[])) public keyToReferred;
+
     /// @notice Adds a new referral key to the list
     /// @param key The referral key to add
     /// @param _cost The cost of the referral program
@@ -161,10 +164,22 @@ contract ReferralRegistry is UUPSHelper {
     /// @param key The referral key for which the user is acknowledging the referrer
     /// @param referrer The address of the referrer
     function acknowledgeReferrer(string calldata key, address referrer) public {
+        if (keyToUserToReferrer[key][msg.sender] != address(0)) {
+            address previousReferrer = keyToUserToReferrer[key][msg.sender];
+            address[] storage previousListOfReferred = keyToReferred[key][previousReferrer];
+            for (uint256 i = 0; i < previousListOfReferred.length; i++) {
+                if (previousListOfReferred[i] == msg.sender) {
+                    previousListOfReferred[i] = previousListOfReferred[previousListOfReferred.length - 1];
+                    previousListOfReferred.pop();
+                    break;
+                }
+            }
+        }
         if (referralPrograms[key].requiresRefererToBeSet) {
             require(refererStatus[key][referrer] == ReferralStatus.Set, "Referrer has not created a referral link");
         }
         keyToUserToReferrer[key][msg.sender] = referrer;
+        keyToReferred[key][referrer].push(msg.sender);
         emit ReferrerAcknowledged(key, msg.sender, referrer);
     }
 
@@ -281,6 +296,13 @@ contract ReferralRegistry is UUPSHelper {
         return keyToUserToReferrer[key][user];
     }
 
+    /// @notice Gets the list of referred users
+    /// @param key The referral key to check
+    /// @param user The referrer
+    function getReferredUsers(string calldata key, address user) external view returns (address[] memory) {
+        return keyToReferred[key][user];
+    }
+
     /// @notice Gets the cost of a referral for a specific key
     /// @param key The referral key to check
     /// @return The cost of the referral for the given key
diff --git a/test/unit/ReferralRegistry.t.sol b/test/unit/ReferralRegistry.t.sol
index 0391201..dc30b74 100644
--- a/test/unit/ReferralRegistry.t.sol
+++ b/test/unit/ReferralRegistry.t.sol
@@ -143,6 +143,50 @@ contract ReferralRegistryTest is Test {
         assertEq(referrer, referrerOnChain);
     }
 
+    function testUserSwitchesReferrer() public {
+        vm.prank(owner);
+        uint256 fee = referralRegistry.costReferralProgram();
+
+        referralRegistry.addReferralKey{value: fee}(referralKey, cost, requiresRefererToBeSet, owner, requiresAuthorization, paymentToken);
+
+        string memory referrerCode1 = "referrerCode1";
+        string memory referrerCode2 = "referrerCode2";
+
+        // Referrer 1 becomes a referrer
+        vm.startPrank(referrer);
+        IERC20(paymentToken).approve(address(referralRegistry), cost);
+        referralRegistry.becomeReferrer(referralKey, referrerCode1);
+        vm.stopPrank();
+
+        // Referrer 2 becomes a referrer
+        address referrer2 = vm.addr(5);
+        vm.startPrank(referrer2);
+        IERC20(paymentToken).approve(address(referralRegistry), cost);
+        referralRegistry.becomeReferrer(referralKey, referrerCode2);
+        vm.stopPrank();
+
+        // User acknowledges referrer 1
+        vm.prank(user);
+        referralRegistry.acknowledgeReferrerByKey(referralKey, referrerCode1);
+        address referrerOnChain = referralRegistry.getReferrer(referralKey, user);
+        assertEq(referrer, referrerOnChain);
+
+        // User switches to referrer 2
+        vm.prank(user);
+        referralRegistry.acknowledgeReferrerByKey(referralKey, referrerCode2);
+        referrerOnChain = referralRegistry.getReferrer(referralKey, user);
+        assertEq(referrer2, referrerOnChain);
+
+        // Assert the list of referred users for both referrers
+        address[] memory referredUsers1 = referralRegistry.getReferredUsers(referralKey, referrer);
+        address[] memory referredUsers2 = referralRegistry.getReferredUsers(referralKey, referrer2);
+
+        assertEq(referredUsers1.length, 0);
+        assertEq(referredUsers2.length, 1);
+        assertEq(referredUsers2[0], user);
+    }
+
+
     function testAcknowledgeReferrerByKeyWithoutCost() public {
         vm.prank(owner);
         uint256 fee = referralRegistry.costReferralProgram();