i m looking a theme for advocate
where advocate can creat there accounts and post their ads and members come and get their numbers
both can create account on website
members as well advocate

It is definitely not worth to even think about such theme 
Anyway, what kind of business are you talking about?

its not only advocate any type of business
for example freelancer creat account in their category
client post his request
same like this theme
https://taskhive.hivepress.io/
but freelancer should creat his account like cv where he mention his education past experiences

Ok if I take Delta theme, rename several strings (Like user - freelancer, item/listing - service) and update contact form in way it will be "Create request", what would I miss? 

in this way this theme is more close to it
https://demo.san-osclass.com/?theme=job
and they are using more attraction

There are different jobs theme but in general, it only need small customization