How to set a blank property

I'm trying to configure Android M

I would like to set erase a persistent property like

getprop | grep dhcp

.../...

[dhcp.wlan0.domain]: [acme.com]

.../..

I would like this property became like this :

[dhcp.wlan0.domain]: []

I tried the setprop command with a blank argument and I got an error message :

 setprop dhcp.wlan0.domain 

usage: setprop NAME VALUE



Sets an Android system property.



setprop: Need 2 arguments

I tried [] as argument and the property has been changed like this :

 [dhcp.wlan0.domain]: [[]] 

I believe this last property is occurring error

Thanks for you help