Who was brought in to try and convince representatives to vote to vote for the 13th amendment? how did they try and accomplish this?

Answer number one:

William Henry Seward (Lincoln's Secretary of State).

Answer number two:

The Thirteenth Amendment of the United States Constitution states that no man should provide involuntary servitude except for punishment for crimes within the United States, this Amendment abolished slavery, and was passed on 1865.

President Abraham Lincoln fought to pass the Emancipation Proclamation, the first step towards ending slavery and named William Henry Seward as his Secretary of State. Seward was a man that also wanted to abolish slavery. He gave multiple speeches stating that no man should be judged by the color of their skin, since every man is equal to eyes of God. He continued Lincoln's job after his assassination. Seward gave great speeches that convinced the Representatives with big support of President Andrew Johnson, who declared that every state that wanted to be part of the Union should adjust to this Amendment.

William Seward certified the Amendment as a part of the United States Constitution in December 6,1865.