You could modify the library file (MaximoSystemLibrary.rptlibrary) and import that but that would impact any (including out of the box and custom reports) inheriting the defaults. What I mean by that is where the style is referenced in the report (such as tabledetailslabel) and they didn't explicitly choose an alignment on that field in the report. This works better (IMO) for text fields but will negatively impact cost information in reports where the numbers would now be aligned to the left which makes it harder to read.
If you don't want to modify the library you would have to export the report, modify the report, and import it. But if the QBR is modified by the user it will be recreated and your changes would be lost.
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Steven Shull
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