Typically builders can make changes to plans that are in “substantial conformance” with the approved plans. These type of changes would include slightly larger/smaller floor plans (usually less than 10%), different gables, porches, etc. Basically, any changes that if a council member who approved the plans drove by the development he wouldn’t be able to notice the changes. If the builder chooses to make changes beyond this scope, the Planning Department would require the builder to return to public hearing (Planning Commission, City Council, etc.) and have the changes heard in front of the commissioners.
If a builder desired to change land use entirely, such as single family to multi-family, etc, that would require a Master Plan Amendment that would also go back to hearing. This would be very costly and time consuming, but entirely possible. However, you would have the opportunity to attend the hearing and make your complaints heard or contact your local council member and let them know your thoughts.
The Master Plan is a legally approved document and would require a legal hearing and new approval for any changes.