Weapon size and Power Armor

[holographic22]

After digging thru threads I see the reason my attacks lower when I put on power armor is due to the weapon size now being off (large armor, medium weapons). Even though the melee weapon shouldn't be effected it is as well.
After replying it's the weapon size the posts say to simply change the weapon size and thread ends...how does one change the weapon size in Starfinder HLO. I will even take tricks to make it show up on statblock correctly.
Thanks all