How do I switch IT providers without downtime?

Switching MSPs feels riskier than it is. A competent incoming provider follows a sequence designed so nothing is ever uncovered: first discovery (documenting your environment, licenses, and vendor relationships while the old provider is still in place), then credential and ownership transfer (admin accounts, domain registrar, Microsoft 365 tenant, moved to YOUR control, not just the new provider's), then parallel onboarding, where the new provider's monitoring and security tools deploy alongside the old provider's.

Only after everything is verified does the actual cutover happen: a coordinated date where your team learns the new number to call. Done this way, employees typically notice nothing except that support got better. The first 30 days afterward are usually spent fixing the accumulated issues the previous provider left and documenting the environment properly.

The one thing that makes switching hard is a departing provider who resists handing over credentials. That's why the ownership question (see 'What should I ask before hiring an MSP?') matters so much before you ever sign.