Create function for booking changes

Skapa en funktion som tillåter administratören att ändra detaljerna för en befintlig bokning, inklusive eventuella tilläggstjänster.

Look for existing booking models and services in the codebase to understand the data structure. Identify the admin API endpoints or controllers where booking operations are handled. The function should update booking details and additional services, so check for validation and database update logic. Test by modifying a booking through the admin interface or API.

Written by the indexing model from the issue text.