no value on channel in blind mode

it's not quite clear what you want. do you want to remove a channel from the complete cuelist? or do you want that starting in a certain cue the channel is not part of that cuelist anymore? the question is what your scenario is. why do you want to do that? the answer to your question depends on what you want to do.

the solution is either At Enter or the Release softkey

You Know like a c chanel on Cobalt

or 3clear on ma 

What Ueli said: To get rid of a channel value in a Cue (or Sub or Preset or....)  in Blind, just type "Channel 1 @ Enter" (no value between @ and Enter means remove).

Just as a sidenote: this is different from 3x Clear on MA because there are no manual (or MA "Programmer") values in Blind in Eos. It is an editing mode so everything gets entered right away.

Cheers :)