Move current Rapid recovery Core server to a new server. Is there a grace or transition period due to license overrun with a temporary extra core server?

There is a grace period of 72 hours, but most importantly Rapid Recovery does not license cores, you can have as many cores as you want/need, what it is licensed is either the amount of machines being protected or the amount of data being protected (depends on your license type). 

Regarding the migration process, you can: 

1. Replicate the data from the old server to the new core How to replace a RapidRecovery or AppAssure Core with minimal downtime (4039917) (quest.com)
2. Archive the data from the old server and import it into the new core How to Move a Protected Server to a new core in AppAssure or Rapid Recovery (4033077) (quest.com)
3. Move the repository from the old server to the new server and attach it

You can take a look at this KB article as well: How to migrate Rapid Recovery Core installation to a new server (4040779) (quest.com). 

There is a grace period of 72 hours, but most importantly Rapid Recovery does not license cores, you can have as many cores as you want/need, what it is licensed is either the amount of machines being protected or the amount of data being protected (depends on your license type). 

Regarding the migration process, you can: 

1. Replicate the data from the old server to the new core How to replace a RapidRecovery or AppAssure Core with minimal downtime (4039917) (quest.com)
2. Archive the data from the old server and import it into the new core How to Move a Protected Server to a new core in AppAssure or Rapid Recovery (4033077) (quest.com)
3. Move the repository from the old server to the new server and attach it

You can take a look at this KB article as well: How to migrate Rapid Recovery Core installation to a new server (4040779) (quest.com). 

Thank you for the reply.
I will use this information to create a plan to move RapidRecovery to a new server.