I saw that you can not chenge the permission set of a user who is already created on HubSpot, if you have not permissions created on the portal.
So I have to look at all the checked or not checked boxes of the permissions set from HubSpot so I can a permission for example sales rep. And then I woudld have to do all that work with all the other permissions.
It would be better if I can change that inside the user already created, so I am recommending this feature idea request.