Thank you for writing in, yes that is possible, first navigate to Licences page and unlock the license that you want to transfer.
Then give that license to your client and ask him/her to register the license to his/her account Licences page, then click on Register License here:
Add in your license numbers this way, then you'll need to add the corresponding URL:
Once you've done that, all your licenses will be in the new account.
More details here.
Thanks for building with X and Pro!