Robyn

[YinYin]

I need them

since some of frames 0-15 are used to holding weapon.

You don't. You can very easily transfer 0-15 to 300-315.

Erm, guess I can't figure out how to do it, could you explain a little?

No, you should've explained why you need them to be 0-15.
If you are just using them when holding that object somewhere you can just use other frames for that.

...

Alright I had a look at it to understand. And now I see Robyn himself is holding objects within that frame range.
Some more thinking and I think I got why you are doing it that way: to not have bat/scythe/etc sticking out of the quiver with their handle cut-off sprites.
Right?
Well I can only suggest the +140 picture shift to make those frames invisible (or showing something different) when not required graphically.