If a profile is open for editing and you have sources, you can update a profile. That is the Collaboration aspect of wikitree.
If you are changing relationships, it is nice to ask a PM about it, just to make sure they don't have a differing opinion, but changes can be made especially with sources being included to back up the changes. When people go in and change parents, spouses, etc and no research notes are added to profiles, no sources are added, that is where some problems come in. Changing dates and locations also with no sources added at the time of changes is also not correct.
If you leave a message on a profile and don't get a response in a week, check the Unresponsive PM process which requires 3 different types of messages to be left, wait a week, then submit the form. Admin will try to get a response and if no response, their deceased people profiles are released and you should be notified so you can then adopt them.
I have received Trusted List access in profiles from PM that have not been active for years, but that always surprises me.