If you want migrate your reseller account into cPanel,You may check the following steps.
First of all we have to create the list of accounts to be transferred using the following command:
cat /etc/trueuserowners | grep resellername |cut -d: -f1 > /home/accountlist.txt
Now account list will be created to be backup.
Now we will create a backup file for all these accounts using below command:
for i in `cat list1.txt`;do /scripts/pkgacct $i /resellerbackup; done
All backup will be created under the folder /resellerbackup once this is done please follow this article to move it to new server and restore it.