The power to reject part of a bill is called a "veto" and is also known as "veto power." When a member of the government (such as governor, Congress or president) vetoes a bill, they are able to either postpone or cancel a decision made by another branch of government.
The party will send a "veto message," which is a document that sets the action in motion. Vetoes are used in many different governments as well as in the United States government. The first congressional override on a presidential veto occurred in 1845 when President John Tyler had vetoed in order to gain unlimited power to appropriate federal funds for new military ships. Congress vetoed this veto because they wanted the president to review all military craft spending with them.