diff --git a/backend/repository/student_sqlite_repository.py b/backend/repository/student_sqlite_repository.py
index 03c7156..b53f6b9 100644
--- a/backend/repository/student_sqlite_repository.py
+++ b/backend/repository/student_sqlite_repository.py
@@ -26,10 +26,11 @@ class StudentSQLiteRepository(AbstractRepository):
     def update(self, student: Student) -> None:
         search_student = self.conn.execute(
             """
-                                           SELECT id FROM students WHERE id=:id
-                                           """,
+            SELECT id FROM students WHERE id=:id
+            """,
             {"id": student.id},
         ).fetchone()
+
         if search_student is None:
             raise StudentRepositoryError(f"The student ({student.id=}) does not exists")
 
diff --git a/backend/service/services.py b/backend/service/services.py
index ab7b884..16ecf88 100644
--- a/backend/service/services.py
+++ b/backend/service/services.py
@@ -74,3 +74,32 @@ def add_student(
 
     conn.commit()
     return student
+
+
+def update_student(
+    id: str,
+    name: str,
+    tribe: str,
+    student_repo: AbstractRepository,
+    tribe_repo: AbstractRepository,
+    conn,
+) -> Student:
+
+    try:
+        _tribe = tribe_repo.get(tribe)
+    except TribeRepositoryError:
+        raise TribeDoesNotExist(
+            f"The tribe {tribe} does not exists. Can't update a student with it"
+        )
+
+    student = Student(id=id, name=name, tribe=_tribe)
+
+    try:
+        student_repo.update(student)
+    except StudentRepositoryError:
+        raise StudentDoesExist(
+            f"The student {student.name} ({student.id=}) does not exists. Can't update it."
+        )
+
+    conn.commit()
+    return student
diff --git a/tests/unit/test_service.py b/tests/unit/test_service.py
index ec91c30..bed89ca 100644
--- a/tests/unit/test_service.py
+++ b/tests/unit/test_service.py
@@ -6,7 +6,12 @@ from backend.repository.abstract_repository import AbstractRepository
 from backend.repository.student_sqlite_repository import StudentRepositoryError
 from backend.repository.tribe_sqlite_repository import TribeRepositoryError
 from backend.service import services
-from backend.service.services import StudentExists, TribeDoesNotExist, TribeExists
+from backend.service.services import (
+    StudentDoesExist,
+    StudentExists,
+    TribeDoesNotExist,
+    TribeExists,
+)
 from tests.model.fakes import build_student, build_tribes
 
 
@@ -53,13 +58,12 @@ class FakeStudentRepository(AbstractRepository):
         else:
             raise StudentRepositoryError(f"{student} already exists")
 
-    def update(self, id: str, student: Student) -> None:
-        try:
-            self._students.pop(id)
-            self._students[student.id] = student
-        except KeyError:
+    def update(self, student: Student) -> None:
+        if student.id not in self._students.keys():
             raise StudentRepositoryError(f"The student {student} does not exists")
 
+        self._students[student.id] = student
+
     def list(self) -> list[Student]:
         return list(self._students.values())
 
@@ -67,7 +71,7 @@ class FakeStudentRepository(AbstractRepository):
         try:
             return self._students[id]
         except KeyError:
-            raise KeyError(f"The student {student} does not exists")
+            raise KeyError(f"The student ({id=}) does not exists")
 
     def delete(self, id: str) -> None:
         try:
@@ -211,3 +215,95 @@ def test_add_student_tribe_doesnt_exist():
         )
 
     assert conn.committed is False
+
+
+def test_update_student():
+    tribes = build_tribes(2)
+    tribe_repo = FakeTribeRepository(tribes)
+    students = build_student(tribes, 1)
+    student_repo = FakeStudentRepository(students)
+    conn = FakeConn()
+
+    id = students[0].id
+    new_name = "new name"
+    new_tribe_name = tribes[1].name
+
+    saved_student = services.update_student(
+        id=id,
+        name=new_name,
+        tribe=new_tribe_name,
+        student_repo=student_repo,
+        tribe_repo=tribe_repo,
+        conn=conn,
+    )
+
+    assert conn.committed is True
+
+    mod_student = student_repo.get(id)
+    assert mod_student.name == new_name
+    assert mod_student.tribe.name == new_tribe_name
+
+    listed_student = student_repo.list()
+    assert len(listed_student) == 2
+
+
+def test_update_student_tribe_doesnt_exists():
+    tribes = build_tribes(2)
+    tribe_repo = FakeTribeRepository(tribes)
+    students = build_student(tribes, 1)
+    student_repo = FakeStudentRepository(students)
+    conn = FakeConn()
+
+    id = students[0].id
+    new_name = "new name"
+    new_tribe_name = "not existing tribe"
+
+    with pytest.raises(TribeDoesNotExist):
+        services.update_student(
+            id=id,
+            name=new_name,
+            tribe=new_tribe_name,
+            student_repo=student_repo,
+            tribe_repo=tribe_repo,
+            conn=conn,
+        )
+
+    assert conn.committed is False
+
+    mod_student = student_repo.get(id)
+    assert mod_student.name == students[0].name
+    assert mod_student.tribe.name == students[0].tribe.name
+
+    listed_student = student_repo.list()
+    assert len(listed_student) == 2
+
+
+def test_update_student_doesnt_exists():
+    tribes = build_tribes(2)
+    tribe_repo = FakeTribeRepository(tribes)
+    students = build_student(tribes, 1)
+    student_repo = FakeStudentRepository(students)
+    conn = FakeConn()
+
+    id = "not existing id"
+    new_name = students[0].name
+    new_tribe_name = students[0].tribe.name
+
+    with pytest.raises(StudentDoesExist):
+        services.update_student(
+            id=id,
+            name=new_name,
+            tribe=new_tribe_name,
+            student_repo=student_repo,
+            tribe_repo=tribe_repo,
+            conn=conn,
+        )
+
+    assert conn.committed is False
+
+    original_student = student_repo.get(students[0].id)
+    assert original_student.name == students[0].name
+    assert original_student.tribe.name == students[0].tribe.name
+
+    listed_student = student_repo.list()
+    assert len(listed_student) == 2