diff --git a/open_humans/views.py b/open_humans/views.py
index f02ea7b24..9ccc51a6f 100644
--- a/open_humans/views.py
+++ b/open_humans/views.py
@@ -370,30 +370,10 @@ def get_context_data(self, **kwargs):
         permissions_changed = False
 
         if "project_id" in self.activity:
-            project_permissions = {
-                "share_username": project.request_username_access,
-                "share_sources": requested_activities,
-                "all_sources": project.all_sources_access,
-                "returned_data_description": project.returned_data_description,
-            }
             if self.activity["is_connected"]:
                 project_member = project.active_user(self.request.user)
-                granted_sources = project_member.granted_sources.all()
-                granted_permissions = {
-                    "share_username": project_member.username_shared,
-                    "share_sources": project_member.granted_sources.all(),
-                    "all_sources": project_member.all_sources_shared,
-                    "returned_data_description": project.returned_data_description,
-                }
-                permissions_changed = not all(
-                    [
-                        granted_permissions[x] == project_permissions[x]
-                        for x in ["share_username", "all_sources"]
-                    ]
-                )
-                gs = set(granted_sources.values_list("id", flat=True))
-                ra = set(requested_activities.values_list("id", flat=True))
-                permissions_changed = permissions_changed or gs.symmetric_difference(ra)
+                granted_permissions = project_member.granted_permissions
+                permissions_changed = project_member.permissions_changed
             if project.no_public_data:
                 public_files = []
 
@@ -412,7 +392,7 @@ def get_context_data(self, **kwargs):
                 "source": self.activity["source_name"],
                 "project": project,
                 "project_member": project_member,
-                "project_permissions": project_permissions,
+                "project_permissions": project.permissions,
                 "granted_permissions": granted_permissions,
                 "permissions_changed": permissions_changed,
                 "public_files": public_files,
diff --git a/private_sharing/models.py b/private_sharing/models.py
index e933431d7..88e995f26 100644
--- a/private_sharing/models.py
+++ b/private_sharing/models.py
@@ -298,6 +298,16 @@ def type(self):
     def authorized_members(self):
         return self.project_members.filter_active().count()
 
+    @property
+    def permissions(self):
+        permissions = {
+            "share_username": self.request_username_access,
+            "share_sources": self.requested_sources.all(),
+            "all_sources": self.all_sources_access,
+            "returned_data_description": self.returned_data_description,
+        }
+        return permissions
+
     def active_user(self, user):
         try:
             return DataRequestProjectMember.objects.get(
@@ -522,6 +532,29 @@ def joined_date(self):
             return None
         return dateutil.parser.parse(self.last_joined[-1][1])
 
+    @property
+    def granted_permissions(self):
+        granted_permissions = {
+            "share_username": self.username_shared,
+            "share_sources": self.granted_sources.all(),
+            "all_sources": self.all_sources_shared,
+            "returned_data_description": self.project.returned_data_description,
+        }
+        return granted_permissions
+
+    @property
+    def permissions_changed(self):
+        permissions_changed = not all(
+            [
+                self.granted_permissions[x] == self.project.permissions[x]
+                for x in ["share_username", "all_sources"]
+            ]
+        )
+        gs = set(self.granted_sources.values_list("id", flat=True))
+        ra = set(self.project.requested_sources.values_list("id", flat=True))
+        permissions_changed = permissions_changed or gs.symmetric_difference(ra)
+        return permissions_changed
+
     @staticmethod
     def random_project_member_id():
         """
diff --git a/private_sharing/views.py b/private_sharing/views.py
index 3587ed91b..9533ef1f4 100644
--- a/private_sharing/views.py
+++ b/private_sharing/views.py
@@ -1,8 +1,12 @@
+import urllib
+
 from django.conf import settings
 from django.contrib import messages as django_messages
 from django.core.exceptions import ObjectDoesNotExist
 from django.http import Http404, HttpResponseRedirect
+from django.shortcuts import redirect
 from django.urls import reverse, reverse_lazy
+from django.utils.encoding import escape_uri_path
 from django.views.generic import (
     CreateView,
     DetailView,
@@ -341,6 +345,35 @@ def form_valid(self, form):
 
         return super().form_valid(form)
 
+    def get(self, request, *args, **kwargs):
+        """
+        Override to reload with an updated parameter forcing reauthorization.
+
+        Without this, an existing project member won't be prompted to
+        reauthorize a project that has updated permissions.
+        """
+        project = self.get_object()
+        try:
+            project_member = DataRequestProjectMember.objects.get(
+                project=project,
+                member=request.user.member,
+                joined=True,
+                authorized=True,
+                revoked=False,
+            )
+            if project_member.permissions_changed:
+                if request.GET.get("approval_prompt", "auto") == "auto":
+                    params = request.GET.copy()
+                    params["approval_prompt"] = "force"
+                    reconstructed = "{0}{1}".format(
+                        escape_uri_path(request.path),
+                        "?" + urllib.parse.urlencode(params),
+                    )
+                    return redirect(reconstructed)
+        except DataRequestProjectMember.DoesNotExist:
+            pass
+        return super().get(request, *args, **kwargs)
+
     def get_context_data(self, **kwargs):
         context = super().get_context_data(**kwargs)