Editing automation

Do you mean you want all the selected nodes to have the same value?

Thanks for your reply. No, I mean if I already did automation for example on strings track and after the whole mix is done , I realize the whole string track or some part of it needs to be 3db loader , is it possible to highlight those parts  and increase the automation 3 db louder just with entering a value? 
Cheers
 

thanks John but still you should use your mouse to move them up and down . it seems there is no way to give them a value to raise or low them.

--I don't know how to do exactly what you want...
 
1. You can flatten all nodes if they have lots of different values by dragging them against the floor or ceiling of the track, letting go, then dragging them back where you want them.
 
2. You can enter a precise value for a single node and then use snap to snap the other values to the same point.
 
3. You can delete all nodes after a certain point and then move the first and last nodes up or down. Or you can enter the precise value for both nodes.
 
I have never needed to set a range of nodes to precisely the same value.
 
I have before wished I could move a set of nodes up and down relatively adjusting rather than with a fixed difference between all the different nodes.

Thanks guys for reply but let me explain it more clear by an example.I hope I can :).   let say i am composing a music for a movie and there are some dialogues already recorded on the same project . so during mixing you realize some part of the FX that you already did properly automation is covering the dialog, and by decreasing a 3db volume problem will solve also you don't want to redo the automation again. I know that we can highlight the FX's automation and move it down by mouse to kill 3db of the volume but let say you wanna do the same thing on 10-15 other parts. each time you try to fix it by mouse it takes time to choose exactly what you want. because of the sensitivity of the mouse they (highlighted values) always jump up and done so fast and take your time to finally seat them in the right place. I wanna save my time and just enter a 3db value to all the highlighted nodes and evenly pull them up.
Thanks Again and Merry christmas.
 

Anderton
It sounds like envelope offset mode is what you want. In envelope mode, a control like a fader will offset the value of the envelope without altering the relationship between the nodes...sort of like a "master volume control" for envelopes.
 
The keyboard shortcut O puts SONAR in envelope offset mode.

Yes but wouldn't that effect all nodes?  I thought he wanted to do this to separate sections leaving most as they are.