• There are many options to reuse contents, but it is unclear what are you searching ... An `article` to `beamer` conversion? Use the `clipboard` package? How copy & paste in LyX? How use children documents (See Menu Insert > File > ...)? To reuse tables could be a good idea copy source LaTeX code of each table in independent `.tex` files and insert ERT boxes with `\input{fileA}` `\input{fileB}` etc. in the main Beamer document (of course, taking care that the preamble have the packages needed for children files (i.e, may be none, may be `booktabs` plus `tabularx`, etc, etc. ).
• Note that in LyX you do not need ERT for `\input`. You can go to Insert > File > Child Document Oct 6, 2014 at 23:34