I'm one of the many network operators at a corporation. One of the board members asks every time, when in her opinion changes are too slow, admin access (credentials) so she can do it herself.
What are the changes, exactly? And why is the board member aware of "the changes"? Are you reporting to the board member?
I denied it every time and I promised I will fix this within 24hrs. And I did.
24 hours is a long time if you want something done yesterday. I'm still not sure why a board member cares about network changes, or even knows about them - can you add more detail?
But this person keeps being stubborn and I'm done with this person's behaviour. How can I politely answer that this person won't get any access?
Hm. This person owns the company, and the C-Suite report to her. In fact, she can vote to fire the C-Suite should she wish. I'm not sure you can be "done" with their behaviour. If the CEO asked this, would you also be similarly "done"?
Also this person often uses MAC-adress spoofing in combination with the UTP-socket of her work computer to get internet access on her notebook. I told her many time she should use the Wi-Fi but she complains about the quality and range.
I don't know what any of that means. Have you attempted to improve the quality of the wifi or come to her with the costs of doing so and what the increase in strength/range would be?
Even worse, she is considering to overrule the network administrators by changing the rules so she would automatically be member and therefore get admin credentials.
Well, if she can do that then she can do that. She owns part of the company, and can vote on new company initiatives. Also, given how competent she appears to be, why is this "even worse"? Has she caused problems in the past?
What can I do?
You can check why your team are reporting to the board, and also why your team are taking a long time to carry out tasks that have such high visibility to the board. Normally these are high priority tasks, but I'm getting the feeling you're putting tasks in a queue and carrying them out, which is silly because it should be priority and not timeliness that determines order.
You can also check the costs to increase the quality of the wifi, and report to this person what those would be.
You can also check why you don't want a highly accomplished person making network changes.
You should finally check your technical credentials at the door. The board run the company, they own stock in the company, and they are typically highly accomplished people - from the sounds of it this person certainly is.
I'm not saying "technical things don't matter", I'm just saying that "technical things don't matter the most", and that actually people's opinions do. Because, in the end, isn't everything just an opinion?
That last sentence is probably a little too philosophical for this site. But certainly be aware that technical issues aren't always the most important.