When a business is sold off, the seller usually keeps providing IT services for a period under a transitional services agreement. The TSA sets the clock for the tenant split: the divested business has to be fully separated before it ends, or the TSA has to be extended at a cost.
Read the TSA first
Check which IT services are covered, for how long, what service levels apply, and what happens at exit. TSAs are often written before anyone has looked at the tenant, so the IT scope may be vague. Clarify it early.
Build the new tenant properly
The divested business needs a new tenant with identity, security, device management and compliance set up before anything moves in. Building it to a secure baseline from the start is far easier than fixing it later.
Scope the data
This is the hardest part. Decide which mailboxes, sites, Teams, shared mailboxes and files go with the business, which stay with the seller, and which are shared. Mixed-use sites and Teams need decisions from business owners, and some content needs legal review. Produce a scoping register early so the decisions are made in time.
Legal hold and records
Content under legal hold, retention policies or eDiscovery cases must stay preserved. Sometimes it has to be kept in both tenants. Map holds and retention before moving anything, and agree the approach with legal.
Identities and devices
People in the divested business get new identities in the new tenant. Plan sign-in for the cutover day and how multi-factor authentication will be registered. Devices need resetting or re-enrolling into the new tenant's Intune, and Autopilot registrations have to move.
Coexistence during the TSA
While the TSA runs, the two businesses may still need to collaborate. Cross-tenant access and federation can provide that, with an end date that matches the TSA exit.
Exit
At TSA exit, cross-tenant access is removed, remaining services end, and the seller confirms the separation. Keep evidence of what was moved, what was retained and when access ended. Both sides will want it.
Planning a tenant migration? Tenant-to-tenant migration
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