Agree on what takes priority
Explain what a new deadline would mean for existing commitments
Your manager asks you to prepare a new report today. You’re also due to send an agreed report today, and you don’t have time to do both. Saying “I have a lot on” communicates that you’re busy, but doesn’t give your manager the information they need to decide.
Name both tasks and suggest realistic options. “I can finish either the report that’s due today or the new one. If the new report takes priority, I can send the other one tomorrow morning. Which deadline matters more?” You can also mention available support or a reduced scope if those are options you’ve agreed on. If a deadline changes, let anyone affected know in good time.
Practice. Say one sentence about your capacity and ask one question about priorities. If you’re clear on the options, try it without using words like “maybe” or “somehow.”