Hey I have this project which I have to hand in by tomorrow, I think my problem is quiet simple one but I'm really new to project management and this softwarre and can not figure it out.

I need to keep the duration of the task but change the hourse that resource works, for example, the task takes 8 days but the person needs to work 4 hours per day. Everytime I change the houre the task duration changes as well. can some one please help with this?