diff --git a/backend/src/main/java/mouda/backend/member/domain/LoginDetail.java b/backend/src/main/java/mouda/backend/member/domain/LoginDetail.java
index 91c33190..2b09c786 100644
--- a/backend/src/main/java/mouda/backend/member/domain/LoginDetail.java
+++ b/backend/src/main/java/mouda/backend/member/domain/LoginDetail.java
@@ -2,7 +2,6 @@
 
 import java.util.Objects;
 
-import jakarta.persistence.Column;
 import jakarta.persistence.Embeddable;
 import jakarta.persistence.EnumType;
 import jakarta.persistence.Enumerated;
@@ -15,7 +14,6 @@ public class LoginDetail {
 	@Enumerated(EnumType.STRING)
 	private OauthType oauthType;
 
-	@Column(unique = true)
 	private String identifier;
 
 	protected LoginDetail() {
diff --git a/backend/src/test/java/mouda/backend/auth/business/KakaoAuthServiceTest.java b/backend/src/test/java/mouda/backend/auth/business/KakaoAuthServiceTest.java
new file mode 100644
index 00000000..a4dc208e
--- /dev/null
+++ b/backend/src/test/java/mouda/backend/auth/business/KakaoAuthServiceTest.java
@@ -0,0 +1,57 @@
+package mouda.backend.auth.business;
+
+import static org.assertj.core.api.Assertions.*;
+import static org.mockito.Mockito.*;
+
+import java.util.Optional;
+
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Test;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.boot.test.mock.mockito.MockBean;
+
+import mouda.backend.auth.implement.KakaoUserInfoProvider;
+import mouda.backend.auth.presentation.request.KakaoConvertRequest;
+import mouda.backend.common.fixture.MemberFixture;
+import mouda.backend.member.domain.Member;
+import mouda.backend.member.domain.OauthType;
+import mouda.backend.member.infrastructure.MemberRepository;
+
+@SpringBootTest
+class KakaoAuthServiceTest {
+
+	@Autowired
+	private KakaoAuthService kakaoAuthService;
+
+	@Autowired
+	private MemberRepository memberRepository;
+
+	@MockBean
+	private KakaoUserInfoProvider userInfoProvider;
+
+	@DisplayName("카카오 회원 정보를 애플 회원으로 변경한다.")
+	@Test
+	void convert() {
+		// given
+		String kakaoIdentifier = "kakaoIdentifier";
+		Member anna = MemberFixture.getAnna(kakaoIdentifier);
+		memberRepository.save(anna);
+
+		String appleIdentifier = "appleIdentifier";
+		Member alternation = MemberFixture.getAnna(OauthType.APPLE, appleIdentifier);
+		memberRepository.save(alternation);
+		when(userInfoProvider.getIdentifier(anyString())).thenReturn(kakaoIdentifier);
+
+		// when
+		kakaoAuthService.convert(alternation, new KakaoConvertRequest("code"));
+
+		// then
+		Optional<Member> kakaoMember = memberRepository.findByLoginDetail_Identifier(kakaoIdentifier);
+		assertThat(kakaoMember.isEmpty()).isTrue();
+		Optional<Member> appleMember = memberRepository.findByLoginDetail_Identifier(appleIdentifier);
+		assertThat(appleMember.isPresent()).isTrue();
+		assertThat(appleMember.get().getName()).isEqualTo(anna.getName());
+		assertThat(appleMember.get().getLoginDetail()).isEqualTo(alternation.getLoginDetail());
+	}
+}
diff --git a/backend/src/test/java/mouda/backend/common/fixture/MemberFixture.java b/backend/src/test/java/mouda/backend/common/fixture/MemberFixture.java
index 811ee9da..4e98d769 100644
--- a/backend/src/test/java/mouda/backend/common/fixture/MemberFixture.java
+++ b/backend/src/test/java/mouda/backend/common/fixture/MemberFixture.java
@@ -27,6 +27,13 @@ public static Member getAnna(String identifier) {
 			.build();
 	}
 
+	public static Member getAnna(OauthType oauthType, String identifier) {
+		return Member.builder()
+			.name("anna")
+			.loginDetail(new LoginDetail(oauthType, identifier))
+			.build();
+	}
+
 	public static Member getChico() {
 		return Member.builder()
 			.name("chico")