Hi The Parent Company has an On Premise Exchange Server 2010. It owns several other Companies that all use the same Exchange Server with different email domains. One of these Companies is separating away and wants to move to Office 365. What would be the best migration option for this? Could I do a Cutover Migration in this scenario, by giving the Migration Account FullAccess ONLY to the Mailboxes of the Company that is moving to Office 365 - Would this be possible? Cutover normally brings everything and I've never done it by just trying to do a subset of mailboxes. PST or Third Party Tools are other options I assume. There are about 400 mailboxes averaging around 3GB. No Rooms, Resources, Groups Thanks

I seem to have found it... Express Migration https://blogs.technet.microsoft.com/exchange/2016/11/28/new-exchange-online-migration-options/

Migrating Subsidiary Company from Exchange to Office 365

Lee Walker
Copper Contributor
May 19, 2017
I seem to have found it... Express Migration
https://blogs.technet.microsoft.com/exchange/2016/11/28/new-exchange-online-migration-options/
Stephan Bisser
Brass Contributor
Jun 21, 2017
Hi,
Does this company already has a hybrid connection in place?
Then you could do it with a remote move migration.
BR
- Lee Walker
  Copper Contributor
  Jun 23, 2017
  Hi
  
  I have installed the Office 365 Hybrid Wizard and using the new Express Minimal Migration method.
  
  https://support.office.com/en-gb/article/Use-Minimal-Hybrid-to-quickly-migrate-Exchange-mailboxes-to-Office-365-fdecceed-0702-4af3-85be-f2a0013937ef?ui=en-US&rs=en-GB&ad=GB
  
  Seems to be going well so far.
  
  Thanks
  Lee
  - Stephan Bisser
    Brass Contributor
    Jun 23, 2017
    Well that's the way to go.
    Migrate via the hybrid connection...
    
    BR
- Microwiz
  Copper Contributor
  Aug 16, 2022
  Stephan Bisser
  How would i preform this if parent company is being nasty, with the situation. wanting Our company to do this manually and within two weeks ? afterward they shut down there servers. we cant access any of the important things to complete steps can you please point me in the right direction. Company A wants Company B out by a certain time, (2wks) but only gives out XL of name files phones and mailboxes Please help