Assume that email@example.com is current "Account Holder" managing Syscloud App and you need firstname.lastname@example.org to be the new account holder/owner.
You can do this by changing the Master Account Contact information (for product related info) in My profile page by following the steps given below.
Login to Syscloud Account
Go to 'My Profile' page using the profile drop down menu at the right top corner (refer pic1).
Change the new account holder/owner email address in the Master Account Contact section. Click on the 'Edit' button and then update the new account holder email address (refer pic2).
Also, in the Backup> Settings> Backup Settings page, in the 'Admin Email Address' section, make sure the user shown is a Super Admin in your GSuite console (refer pic3). If it is not the case then please update the appropriate Super Admin email address and Save the settings. Note that if you have multiple domains added in the Syscloud account, you will have to check this Backup Setting for each of the domain by selecting the dropdown in the page.