I'm returning to Lego as an adult and struggling with what I thought would be a small project.

Please tell me if this is off topic but as it has a hard answer of no or this is how I though it would be ok.

What I'm trying to do is change the pose of the Lego Mario Yoshi but the way it is built I cant see any way of moving anything.

The goal is from this:

to this:

Can anyone tell me how I would go about this or is the original design too limiting to make it a possibility?