The previous two posters did not mention that a reassessment of the strata will be required. That involves a surveyor to draw up new strata plans that include your additions, a new valuation of the unit entitlements , getting the motion passed to alter the strata scheme, and r hen registration of the scheme.
It’s all at the cost of the owner.
It’s not impossible and I’m certain it’s been done by a determined owner.
But you need to go 8n with eyes wide open, be aware of all the costs and the hurdles you have to jump.
As the previous poster said, you need to make sure that all owners are supportive and remain so for the duration.
Remember that the new strata plan and revaluation occur after you have finished the build. You don’t want it to go pear shaped at that stage.
Just consider whether this is a vanity project or whether the build will add value to your property. (The answer is that it adds no value because you will pay the OC the increase in value) It may be easier to just purchase a property with the views you seek.