How many free acounts with standard plan?

How many free acounts with standard plan?

Hello,

     Currently I have been tested Zoho CRM whit 3 free users. I noted that at the beginning  I need only one user nwith standards plan functions and probably gorwing up  bussines it could be necessary upgrade the plan and add more users. So, If upgrade the plan of one user to standard plan:

1.- I will lose relations with another accounts?

2.- Could I change user permission?

Thanks in advance.