During your career, you need to respond effectively to hard requests put upon you. Here’s a technique that will help.
If someone approaches you with a request, respond with “How am I supposed to do that?” (in a polite and considered way of course).
The question disarms the asker in a few ways. Many requests are made impulsively (ie, urgent but not-important), and this question helps clarify if the request has been fully formed. If you are struggling with capacity, or this request shouldn’t be in your court, the question helps frame your position. The question also invites the other person to collaborate, which is more effective than a soft or hard no.
This technique is courtesy of Chris Voss, author of Never Split The Difference: Negotiating As If Your Life Depended On It. It’s a thoroughly good read.