lease extension

If someone tried to force a lease extension
because of "major structural repair improvements" what would this mean? Would that have to be an improvement to an existing structure or could they just add something new to the property without permission or the lessors knowlege? This is in the state of Louisiana. Any advice, or input would be appreciated.

What do you mean by "force a lease extension"? Are they trying to change some conditon of the lease (like the amount of rent or what you can or cannot do under the lease) or are they trying to change what the lease covers (like they're building a new building on the property)? It also makes a difference whether you are talking about commercial or residential property.