Hello Dear, I've read your project description and I can Implement functionalities improve and make changes in the resolution for your existing CRM for appointment / calendar management as per your requirements. Let's have a quick discussion about the project.
We have extensive experience in designing and developing Portals, Web and Mobile application, E-commerce in all major platforms, etc.
I am sharing our portfolio with you have a look,
https://www.freelancer.com/u/junkyfunky
Thanks,
Faizan