Some of the first colonists in this country were political and religious refugees. Rhode Island was founded by refugees fleeing other colonial refugees. Many of our founding fathers were immigrants. 

Our Constitution was changed to stop those who felt they had they God given right to own other people. It was changed to allow those who didn’t own land, and women, and African Americans the right to vote.
Those who wrote the original words admitted that the document they created, that they as people, were not infallible. They admitted that they could not see into the future, and that we may need to make adjustments. 
Thomas Jefferson himself said, “I am not an advocate for frequent changes in laws and constitutions, but laws and institutions must go hand in hand with the progress of the human mind. As that becomes more developed, more enlightened, as new discoveries are made, new truths discovered and manners and opinions change, with the change of circumstances, institutions must advance also to keep pace with the times. We might as well require a man to wear still the coat which fitted him when a boy as civilized society to remain ever under the regimen of their barbarous ancestors.“
The fact that our founders knew that we needed to create a new form of government and leave the monarchy behind meant that they understood that the needs of a country change as time passes. Things that once worked, no longer do.
Change isn’t bad. We haven’t left a great America in the past by opening our arms to immigrants and refugees. We are still living by the good, just ideals of our founders. The only things we’ve tried to leave behind are slavery, and patriarchy.  And we aren’t weakening a document by asking for changes. We’re strengthening it by showing that it can grow and metamorphose over time. That the needs of the country, and its citizens, can be taken into account, and readdressed. There is no “New World” to go to for a fresh start. We have to create our fresh starts out of the ashes of our failures. We have to recognize our shortcomings, the parts of our law that don’t work as intended, or that no longer function well within modern society, and we have to reassess, reexamine, and be willing to move forward. Or we will collapse under the weight of our past.