Merging child company SEP clients into parent company SEPM

Hi,

Our company (X) was recently accquired by another company (Y). We (X) had our own SEP enivronment and the company (Y) that accquired us had their own SEP environment. Both companies SEPMs are running on version 12.1.6. Now the parent company (Y) wants to move all existing SEP endpoints in our (X) environment to their SEPM for consolidation. Our (X) SEPM will subsequently be decomissioned afterwards. What is the best way to achieve this? Also can we (X) import our licenses into their (Y) SEPM for use?

Thanks.