DHCP Scope for Switch Management

[Tausif-M]

Dears

We are facing a problem related to the DHCP Scope for Switch Management. The scope is full & we need to add more switches.
It can be acheived by changing the current scope directly but it will result in downtime & moving to different  locations to change the scope through CLI.

I will provide the details below, please put your needful comments:

Core 1: 192.168.80.1/24
Core 2: 192.168.80.2/24
Subnet: 255.255.255.0

We would like to move to /22 subnet i.e 255.255.252.0.

Please help me how can i acheive this without making any changes to existing Vlan & adding a new Vlan for Switch Management with IP Range 192.168.84.0/22. 

Regards

Tausif