The purpose of the Constitutional Convention was to revise the Articles of Confederation.
The revised "Articles of Confederation" were renounced and after a debate, they were in favor of creating a new "Constitution of the United States".The convention had been termed to meliorate on the Articles. However, the convention was not called to do what it ended up doing. What it ended up doing was creating an entirely new constitution. This new constitution (i.e today's) much more strengthen the federal government than it had had under the Articles of Confederation.