I don't think you can change status of any extension even as admin. This is still a feature request I can see here:

https://ideas.ringcentral.com/ideas/ENTCOM-I-56

Please vote for this idea if is similar to your requirement

Mayank
Our company, RSI, is a RingCentral ISV Partner. We have a possible solution to your request. The product is called Shadow Agent.

It allows authorized persons the ability to change another person's status (i.e. Busy -> Available, DND etc.) It also allows for custom statuses such as On Break, On Lunch etc.

There is also a built-in Queue View, Leaderboard and Extension View that shows all colleagues available in the group(s).

Here is the listing on the RingCentral App Gallery:
https://link.telecost.com/shadowa

If you are an Admin , you should be able to change the presence status of the user by using this endpoint https://developers.ringcentral.com/api-reference/Presence/updateUserPresenceStatus and change user status of other extensions

Please let me know if this suffice.