diff --git a/src/Pointers/Pointer.php b/src/Pointers/Pointer.php
index 43bf9bc..b553cb3 100644
--- a/src/Pointers/Pointer.php
+++ b/src/Pointers/Pointer.php
@@ -113,7 +113,7 @@ final class Pointer implements Stringable
      * @param mixed $key
      * @return mixed
      */
-    public function call(mixed $value, mixed $key): mixed
+    public function call(mixed $value, mixed &$key): mixed
     {
         if ($this->callback === null) {
             return $value;
diff --git a/src/ValueObjects/State.php b/src/ValueObjects/State.php
index e88da0a..15fc273 100644
--- a/src/ValueObjects/State.php
+++ b/src/ValueObjects/State.php
@@ -51,7 +51,7 @@ final class State
      */
     public function __construct(private Pointers $pointers, private Closure $lazyLoad)
     {
-        $this->tree = new Tree($this->pointers);
+        $this->tree = new Tree($pointers);
     }
 
     /**
@@ -91,7 +91,7 @@ final class State
      * @param mixed $key
      * @return mixed
      */
-    public function callPointer(mixed $value, mixed $key): mixed
+    public function callPointer(mixed $value, mixed &$key): mixed
     {
         return $this->pointers->matching()->call($value, $key);
     }
@@ -107,11 +107,15 @@ final class State
         $this->tree->traverseToken($token, $this->expectsKey);
 
         if ($this->tree->isMatched() && ((!$this->expectsKey && $token->isValue()) || $this->tree->isDeep())) {
-            $shouldLazyLoad = $token instanceof CompoundBegin && $this->pointers->matching()->isLazy();
-            /** @phpstan-ignore-next-line */
-            $this->buffer = $shouldLazyLoad ? ($this->lazyLoad)() : $this->buffer . $token;
-            /** @var CompoundBegin $token */
-            $shouldLazyLoad && $token->shouldLazyLoad = true;
+            $this->pointers->markAsFound();
+
+            if ($token instanceof CompoundBegin && $this->pointers->matching()->isLazy()) {
+                $this->buffer = ($this->lazyLoad)();
+                $token->shouldLazyLoad = true;
+            } else {
+                /** @phpstan-ignore-next-line */
+                $this->buffer .= $token;
+            }
         }
 
         $token->mutateState($this);
diff --git a/tests/Dataset.php b/tests/Dataset.php
index 351c89a..18b0545 100644
--- a/tests/Dataset.php
+++ b/tests/Dataset.php
@@ -96,6 +96,23 @@ final class Dataset
         yield from self::forSinglePointersWithFixture('pointers/single_pointer_to_array.php');
     }
 
+    /**
+     * Retrieve the dataset to test the key update
+     *
+     * @return Generator
+     */
+    public static function forKeyUpdate(): Generator
+    {
+        $json = fixture('json/complex_object.json');
+        $pointers = [
+            '/type' => function ($value, &$key) {
+                $key = 'foo';
+            },
+        ];
+
+        yield [$json, $pointers, ['foo' => 'donut']];
+    }
+
     /**
      * Retrieve the dataset to test multiple pointers
      *
diff --git a/tests/Feature/PointersTest.php b/tests/Feature/PointersTest.php
index d7d7298..1f10475 100644
--- a/tests/Feature/PointersTest.php
+++ b/tests/Feature/PointersTest.php
@@ -23,6 +23,10 @@ it('eager loads lazy pointers into an array', function (string $json, string $po
     expect(JsonParser::parse($json)->lazyPointer($pointer)->toArray())->toBe($expected);
 })->with(Dataset::forSinglePointersToArray());
 
+it('can modify key and value of a pointer', function (string $json, array $pointers, array $expected) {
+    expect(JsonParser::parse($json)->pointers($pointers)->toArray())->toBe($expected);
+})->with(Dataset::forKeyUpdate());
+
 it('loads JSON from multiple JSON pointers', function (string $json, array $pointers, array $parsed) {
     expect(JsonParser::parse($json)->pointers($pointers))->toPointTo($parsed);
 })->with(Dataset::forMultiplePointers());