Selective gain increase of an audio region

[globet]

If possible, would like to increase the gain of the red selection section of the audio region. Any ideas? 

[oscwilde]

Choose/use the Gain tool.

[globet]

40 minutes ago, oscwilde said:

Choose/use the Gain tool.

The Gain Tool or using the Gain function from the inspector puts Gain on the whole region. Need it selectively on a specific section of the audio region. Can cut out the section with the Marquee tool and apply Gain but would like to avoid that.

[oscwilde]

Yes, per your image of the Track/Region editor - the gain can be selectively applied to part of the region with the marquee tool.
This will split the region.

You can destructively edit the audio FILE in the Audio FILE Editor.
Choose an audio file from the file browser or region (that points to the underlying file) in the Arrange.
Press CMD-6....or double-click the Arrange region, then switch from the Track/Region editor to the Audio (File) Editor by pressing the File button.
Select the portion of the file you want to adjust with the Pointer tool.
Choose Functions > Change Gain (or press Ctrl-G).
In the Change Gain dialog, make your adjustments and press Change.
You might see a warning dialog about Undo...depending on your app/project settings.

As a suggestion....unless you know the audio file is not going to be used in another project - make a copy of the underlying file and work on this copy (or use the original and move the copy somewhere safe).
In essence, if the file is reused in another project, the gain change(s) will be "baked in".