Need to upgrade VMWare Esxi hosts from 5.0 to 6.5

Hi,

I need to upgrade VMWare Esxi hosts from 5.0 to 6.5 version.

My Hardware is Cisco UCS B200 M2 Blade Servers and all the blade Servers are in HA in 5.0 Esxi and there are around 50 VMs running on it.

Please guide me step by step process or procedure for doing the above migration with out impacting these 50 VMs.

Looking forward your reply at the earliest.

Regards

Sanjeevi