Is it possible a Taurus and a Scorpio to change their roles?!

Is it possible a Taurus and a Scorpio to change their roles?

The Scorpio becomes more forgiving and forgetful, unusually nice at times and kind while the Taurus starts to plan a revenge and to become fierce.

I am also wondering myself what happening with me, I started to behave stingy and trying to answer back each time, while my Scorpio friend started to be nice and polite like never before.

Actually I won't revenge as I had the feeling I want to once, I stopped myself from it because I felt scared I am not the kind and helpful Taurus anymore. I hope I will go back to my Taurus status soon.

Don't be fooled by the apparent nice & calm nature of your Scorpio mate. Note my use of the word 'apparent' here. ;)
Scorpio and Taurus can be similar because they're both mentally strong, determined, passionate and are pretty quick to anger.

The fact that you became more stingy and impulsive is not a sign that you are changing. It is only an evidence of your relationship with your Scorpio. Living with a Scorpio's nature and getting used to it makes your character model itself according to the character of the Scorpio.
Regardless of your astrological sign, gender or age, most people, would model some of their personality parts according to the personality of the people they live with constantly.

It's very likely that you react like this because the constant pressure coming from the Scorpio mate made you build up certain reflexes in your personality. After the Scorpio stops acting like that, you keep acting in the same impulsive manner because this manner already became an automatic reflex.

As for the Scorpio being nice & polite... This is probably a plot coming from your mate. ;) Scorpios are rarely submissive and they respond quickly to challenges, especially in relationships. The most probable reason for your Scorpio's peaceful attitude is the fact that they're plotting revenge. Scorpios like to manipulate through guilt or revenge or mind games. So be careful, they use psychology as a weapon. If something seems suspicious to you in their attitude, they're up to something.