This is a common proceedure.
Either screw or hydraulic jacks will be used to slightly raise the center beam .... just enough to take the weight off the existing support columns for removal or for shortening..... depending on what the existing support columns are made of.
The jacks will be slowly lowered to bring the center down to reasonably level .... the shortened support columns will then be installed permanently.
It might be new columns can be installed and may be adjustable columns called teleposts ... they may be steel 4 inch square tube with a large threaded rod or a round steel column with a similar threaded rod used for adjutment.
It's not uncommon for foundation repair companies to do this or a general contractor.
Hope this helps.
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