In 1823, U.S. President James Monroe issued the Monroe Doctrine. It stated that no European nation should intervene in any situations in North or South America, and in return, the United States would not meddle in European affairs. It was originally intended to protect the newly freed South American countries, once Spanish colonies. The Roosevelt Corollary had the same fundamental principals, and therefore did not alter the nature of the doctrine or the intentions of its original authors.
The basis of the corollary was that it gave the United States justification to protect the Latin American countries from European countries seeking to re-claim debts.
This is nearly identical to the South American protection the Monroe Doctrine was attempting to justify. So, in terms of their basic intentions, the Roosevelt Corollary was not different from the Monroe Doctrine.
Second, the Roosevelt Corollary only made the Monroe Doctrine stronger. This is because the justification of the Doctrine was shady at best, and would always be military interference.
However, the Corollary made it stronger by allowing non-military protection, through the absorption of debts. This method kept all sides happy, and protected the already soiled reputation of the United States.
Finally, the ultimate intention of both the Monroe Doctrine and the Roosevelt Corollary was to prevent further European colonization of the Americas. This was stated directly in the Monroe Doctrine, and the Roosevelt Corollary was preventing any indirect seizures of any country through debts. So, in general, the Roosevelt Corollary was a way of updating the Monroe Doctrine to make it more powerful, and foolproof.
In summation, the Roosevelt Corollary did not fundamentally alter the Monroe Doctrine. Their basic purposes were nearly identical, the Corollary only strengthened the Doctrine s message, and their ultimate intentions were the same. In the end, they worked together to completely end European colonization of the Americas, which was exactly what they were intended to do.