Withdrawing politely keeps the door open for next time. Fill in the boxes and the email writes itself.
Filled in with an example. Type in the boxes to make it yours.
Subject: Withdrawing my application: Business Analyst
Hi Rachel,
Thank you for your time on the Business Analyst role. I have decided to withdraw my application, as I have accepted another position.
I enjoyed learning about the team, and I would be glad to be considered for future roles.
Kind regards,
Sam Hollis
Tell them as soon as you decide, especially if interviews are booked. A short reason helps them close the role, but you do not owe a detailed one.
Keep it warm: the recruiter or hiring manager may well have another role you want later.
More on this: How to withdraw a job application without burning a bridge
Keep every letter with the job it belongs to: jobtracker.co.nz is free while you're between jobs. See all the letter templates.