The 25-year-old, who portrays domestic violence victim Jo Sugden, intended to leave the show last year, but producers convinced her to stay for another 12 months.
Her current storyline has seen Jo suffer at the hands of husband Andy Sugden (Kelvin Fletcher) and over the next few months, his torment intensifies until a neighbour intervenes.
A source told The Sun: "Roxanne wanted to leave last year but the producers put her at the centre of this big storyline, which is only going to get more harrowing.
"Now she has agreed her leaving terms and will go in a huge exit in December."
Series producer Anita Turner added: "Roxanne has given a fantastic performance and it will be an eventful six months for Jo."
Now, Pallett is determined to crack the West End as she intends to move to London in a bid for theatre fame.
In October, Pallett ended her two-year relationship with Richard Fleeshman, who played Craig Harris in Coronation Street. The pair met while competing in Soapstar Superstar, which Fleeshman subsequently went on to win.