If you need support from Yola please contact us via firstname.lastname@example.org or make use of our live chat service! We are working on a new approach to community-based support and during this transition period we are not adding any new threads to this forum. Many thanks to everyone who has participated over the years and we look forward to unveiling a new peer-to-peer support system soon!
The only way someone else can edit your site is if you give them your login email and password. Unfortunately we don't yet have a feature where you can setup multiple logins and passwords to edit the same site.
My best suggestion is that you create a separate account for the site you want to collaborate on and share these login details with the relevant people. This way you can keep the shared site separate from any other sites in your account.
I'm sorry we can't be of more help in this regard.