You can always change the definitions of your variables individually in Configuration > Common Properties > Text Variables in the Project Explorer. In addition to this you can set different values for specific variables in individual topics. When you publish your project you can also redefine some or all of the variables in your entire project with a project skin or a variable definitions file.
If you want a variable to have a different value in individual topics you can redefine it in the Topic Options tab on the left of the main editor window when the topic is select ed. Note that this is only possible with user-defined variables. You cannot define Help+Manual's standard variables with this feature.
1.Select the topic in the Project Explorer, then select the Topic Options tab on the left of the main editor window.
2.Click on the + button next to the Topic Variables box at the bottom of the window.
3.Select the variable you want to redefine and click OK, this adds the variable to the Topic Variables list.
4.Click in the Value field and enter a new value. The values you enter here will only be used in the current topic.
See The power of editable variables for more information on the kind of things you can do with this feature.
When you publish your project you can redefine some or all of the variables in the entire project in two different ways: With "skins" and with the command line compilation feature.
Redefining variables with publishing tasks
The Publishing Task Manager makes it possible to define "tasks" to publish your project to multiple output formats and destinations in a single integrated operation. In addition to this you can also redefine the variables in your project when you publish the task with a list of alternative variable definitions. See Publishing to multiple formats for instructions.
Redefining your variables with skins:
Note that you can also assign skins to publishing tasks.
1.Create a project skin (only possible with Help+Manual Professional) containing the alternative definitions of your variables (and anything else you want to change in your project). If you only want to redefine your variables you can create a skin that only contains your variable definitions. See Transforming Your Output with Skins for more details.
Note that skins can't be selected in the Publish dialog in non-HTML formats – you need to use command line publishing (see below) for those formats where skins are not directly available.
Redefining your variables from the command line:
You can also create a simple text file containing a list of definitions of the variables you want to change. You can then specify this file in the command line to redefine all the variables in your project with the values in the file.
In addition to this you can also specify a project skin file in the command line, to apply a completely different appearance to the entire project as well as redefining the variables.
Variables and Conditional Output (Reference)