diff --git a/data/uking_functions.csv b/data/uking_functions.csv
index 8d94952c..178a9b94 100644
--- a/data/uking_functions.csv
+++ b/data/uking_functions.csv
@@ -75585,12 +75585,12 @@
 0x0000007100db3ffc,evt::Event::doAssign,296,
 0x0000007100db4124,evt::Event::assign,48,
 0x0000007100db4154,sub_7100DB4154,1680,
-0x0000007100db47e4,ksys::evt::OrderParam::ctor,36,_ZN4ksys3evt10OrderParamC1EPN4sead7ExpHeapE
+0x0000007100db47e4,ksys::evt::OrderParam::ctor,36,_ZN4ksys3evt10OrderParamC1EPN4sead4HeapE
 0x0000007100db4808,ksys::evt::OrderParam::dtor,20,_ZN4ksys3evt10OrderParamD1Ev
 0x0000007100db481c,ksys::evt::OrderParam::uninitialize,284,_ZN4ksys3evt10OrderParam12uninitializeEv
 0x0000007100db4938,ksys::evt::OrderParam::dtorDelete,52,_ZN4ksys3evt10OrderParamD0Ev
-0x0000007100db496c,ksys::evt::OrderParam::doAssign,1160,_ZN4ksys3evt10OrderParam8doAssignEPS1_
-0x0000007100db4df4,ksys::evt::OrderParam::assign,48,_ZN4ksys3evt10OrderParam6assignEPS1_
+0x0000007100db496c,ksys::evt::OrderParam::doAssign,1160,_ZN4ksys3evt10OrderParam8doAssignERKS1_
+0x0000007100db4df4,ksys::evt::OrderParam::assign,48,_ZN4ksys3evt10OrderParamaSERKS1_
 0x0000007100db4e24,ksys::evt::OrderParam::initialize,332,_ZN4ksys3evt10OrderParam10initializeEi
 0x0000007100db4f70,ksys::evt::OrderParam::addParamInt,220,_ZN4ksys3evt10OrderParam11addParamIntEiRKN4sead14SafeStringBaseIcEE
 0x0000007100db504c,ksys::evt::OrderParam::addParamString,412,_ZN4ksys3evt10OrderParam14addParamStringERKN4sead14SafeStringBaseIcEES6_
diff --git a/src/KingSystem/Event/evtOrderParam.cpp b/src/KingSystem/Event/evtOrderParam.cpp
index 30ff8211..1168fa2d 100644
--- a/src/KingSystem/Event/evtOrderParam.cpp
+++ b/src/KingSystem/Event/evtOrderParam.cpp
@@ -1,5 +1,4 @@
 #include "KingSystem/Event/evtOrderParam.h"
-#include <basis/seadTypes.h>
 #include <codec/seadHashCRC32.h>
 #include <container/seadBuffer.h>
 #include <heap/seadExpHeap.h>
@@ -8,7 +7,7 @@
 
 namespace ksys::evt {
 
-OrderParam::OrderParam(sead::ExpHeap* heap) {
+OrderParam::OrderParam(sead::Heap* heap) {
     mHeap = heap;
 }
 
@@ -77,26 +76,28 @@ const OrderParamEntry* OrderParam::getParam(const s32 index) const {
     sead::FixedSafeString<0x100> error_message;
 
     error_message.format("[%s] getParam(%d) is failed.", "ksys::evt::OrderParam", index);
-    if ((u32)std::max(0, mEntries.size()) > (u32)index) {
+    if (u32(std::max(0, mEntries.size())) > u32(index)) {
         return &mEntries[index];
     } else {
         return nullptr;
     }
 }
-OrderParam* OrderParam::assign(OrderParam* other) {
-    if (this != other) {
+
+OrderParam& OrderParam::operator=(const OrderParam& other) {
+    if (this != &other) {
         doAssign(other);
     }
-    return this;
+    return *this;
 }
 
-bool OrderParam::doAssign(OrderParam* other) {
-    if (this == other)
+bool OrderParam::doAssign(const OrderParam& other) {
+    if (this == &other)
         return true;
-    if (!initialize(std::max(0, other->mEntries.size())))
+
+    if (!initialize(std::max(0, other.mEntries.size())))
         return false;
     for (s32 i = 0; i < mEntries.size(); i++) {
-        auto* other_entry = other->getParam(i);
+        auto* other_entry = other.getParam(i);
         if (other_entry) {
             auto* other_ptr = other_entry->data;
             auto* other_name = other_entry->name;
diff --git a/src/KingSystem/Event/evtOrderParam.h b/src/KingSystem/Event/evtOrderParam.h
index 7f3f8696..5498a307 100644
--- a/src/KingSystem/Event/evtOrderParam.h
+++ b/src/KingSystem/Event/evtOrderParam.h
@@ -27,15 +27,15 @@ struct OrderParamEntry {
 };
 
 class OrderParam {
-    OrderParam(sead::ExpHeap* heap);
-    virtual ~OrderParam();
-
 public:
+    explicit OrderParam(sead::Heap* heap);
+    OrderParam(const OrderParam& other) { *this = other; }
+    virtual ~OrderParam();
+    OrderParam& operator=(const OrderParam& other);
     bool initialize(s32 entry_count);
     void uninitialize();
-    OrderParam* assign(OrderParam* other);
 
-    inline const OrderParamEntry* getParam(const s32 index) const;
+    const OrderParamEntry* getParam(s32 index) const;
     bool addParamInt(s32 val, const sead::SafeString& name);
     bool addParamFloat(f32 val, const sead::SafeString& name);
     bool addParamString(const sead::SafeString& val, const sead::SafeString& name);
@@ -49,7 +49,8 @@ public:
     bool getArrayByName(const sead::SafeString& name, void** out_ptr, u32* out_size);
 
 private:
-    bool doAssign(OrderParam* other);
+    bool doAssign(const OrderParam& other);
+
     OrderParamEntry* getFreeEntry();
     void* getPointerByName(const sead::SafeString& name, OrderParamType type,
                            u32* out_size = nullptr) const;
@@ -84,7 +85,7 @@ private:
         e->data = nullptr;
     }
 
-    sead::ExpHeap* mHeap;
+    sead::Heap* mHeap;
     sead::Buffer<OrderParamEntry> mEntries;
     u32 mEntryCount = 0;
     bool mInitialized = false;