How to update active and stadby nodes separetly?

Question

I need to update the slave node at first to the latest firmware version and then the active node, so as to run the firewall without any interruptions.

nd · Answer

In Active-Passive setups you can configure it to update only one device, so at first the master will update, then the slave switches to master role while the old one will update firmware. After that you can reboot the new master so the old one switches back to master role.

"keep nodes reserved during up2date"

SDk · Answer

Can I update the slave at first and restart it without updating the Master. 
 So I would like to update the Master after a few days.