How Can I Reduce My Paper Size but Still Retain the Dims of Objects on the Paper?

I have a file that I drew using version 12. The file's paper size is 100 feet wide which depicts my property lot size.

The file contains (among other items) a fence that I drew on a 1:1 scale. I drew the pickets to be 5.5 inches wide by 6 feet tall.

Now I would like to reduce the paper size to 8.5 X 11 but retain the sizes of the wood that I drew. For example:

After reducing the paper size, if I select a picket, the displayed width of a picket that I drew (i.e, that's shown in the bottom left of the Corel screen) should still read 5.5".

The manual is not too clear on how I can do this. Can somebody please help me?