Migrating your site without downtime is important for your visitors and traffic. Here's how you can do this.
- Sign up for the new hosting plan
- Migrate the files/database and site from the old hosting plan, while keeping the old plan active and the original files there (Migration Guides for cPanel, Plesk, and WordPress).
- Change your nameservers or domain's Apex record to those of the new plan. (Guide)
- Wait 24-48 hours for the DNS to propagate, then you can cancel the old hosting plan.
This way, you ensure that regardless of the status of DNS propagation for a user, they will either hit the new server or the old server, with both containing an active website, ensuring a seamless transition.