So I am new to resourcing. Say I have task 1 that starts January 1 and ends December 31. I need to work on task 1 50% of my time every week. However a new task 2 comes up where I need to work 60% of my time all next week. Is there a way to change the % worked for task 1 to 40% for just next week without changing dates and leveling?

Sure - go into the Task Usage view and modify the scheduled work for the week. It will recalculate the assignment units for that one week.