diff --git a/app.py b/app.py
index 9429bc9..d4c2f34 100644
--- a/app.py
+++ b/app.py
@@ -256,5 +256,35 @@ def calculate_work_duration(arrival_time, departure_time, total_break_duration):
 
     return work_duration, effective_break_duration
 
+@app.route('/api/resume/<int:entry_id>', methods=['POST'])
+def resume_entry(entry_id):
+    # Find the entry to resume
+    entry_to_resume = TimeEntry.query.get_or_404(entry_id)
+
+    # Check if there's already an active entry
+    active_entry = TimeEntry.query.filter_by(departure_time=None).first()
+    if active_entry:
+        return jsonify({
+            'success': False,
+            'message': 'Cannot resume this entry. Another session is already active.'
+        }), 400
+
+    # Clear the departure time to make this entry active again
+    entry_to_resume.departure_time = None
+
+    # Reset pause state if it was paused
+    entry_to_resume.is_paused = False
+    entry_to_resume.pause_start_time = None
+
+    db.session.commit()
+
+    return jsonify({
+        'success': True,
+        'message': 'Work resumed on existing entry',
+        'id': entry_to_resume.id,
+        'arrival_time': entry_to_resume.arrival_time.strftime('%Y-%m-%d %H:%M:%S'),
+        'total_break_duration': entry_to_resume.total_break_duration
+    })
+
 if __name__ == '__main__':
     app.run(debug=True)
\ No newline at end of file
diff --git a/static/js/script.js b/static/js/script.js
index 218e2c4..1fb14b9 100644
--- a/static/js/script.js
+++ b/static/js/script.js
@@ -133,3 +133,52 @@ document.addEventListener('DOMContentLoaded', function() {
         });
     }
 });
+
+// Add event listener for resume work buttons
+document.addEventListener('click', function(e) {
+    if (e.target && e.target.classList.contains('resume-work-btn')) {
+        const entryId = e.target.getAttribute('data-id');
+        resumeWork(entryId);
+    }
+});
+
+// Function to resume work
+function resumeWork(entryId) {
+    fetch(`/api/resume/${entryId}`, {
+        method: 'POST',
+        headers: {
+            'Content-Type': 'application/json',
+        }
+    })
+    .then(response => {
+        if (!response.ok) {
+            return response.json().then(data => {
+                throw new Error(data.message || 'Failed to resume work');
+            });
+        }
+        return response.json();
+    })
+    .then(data => {
+        if (data.success) {
+            // Show a notification
+            const notification = document.createElement('div');
+            notification.className = 'notification';
+            notification.textContent = data.message;
+            document.body.appendChild(notification);
+
+            // Remove notification after 3 seconds
+            setTimeout(() => {
+                notification.remove();
+            }, 3000);
+
+            // Reload the page to show the active session
+            window.location.reload();
+        } else {
+            alert(data.message);
+        }
+    })
+    .catch(error => {
+        console.error('Error:', error);
+        alert(error.message || 'An error occurred while trying to resume work.');
+    });
+}
\ No newline at end of file
diff --git a/templates/index.html b/templates/index.html
index bf84df1..098ba94 100644
--- a/templates/index.html
+++ b/templates/index.html
@@ -65,6 +65,9 @@
                         <td>{{ '%d:%02d:%02d'|format(entry.duration//3600, (entry.duration%3600)//60, entry.duration%60) if entry.duration is not none else 'In progress' }}</td>
                         <td>{{ '%d:%02d:%02d'|format(entry.total_break_duration//3600, (entry.total_break_duration%3600)//60, entry.total_break_duration%60) if entry.total_break_duration is not none else '00:00:00' }}</td>
                         <td>
+                            {% if entry.departure_time and not active_entry %}
+                            <button class="resume-work-btn" data-id="{{ entry.id }}">Resume Work</button>
+                            {% endif %}
                             <button class="edit-entry-btn" data-id="{{ entry.id }}">Edit</button>
                             <button class="delete-entry-btn" data-id="{{ entry.id }}">Delete</button>
                         </td>