The number of Path of exile currency their colour, sockets and relations can be changed using several items

The Orb of jeweller - allows you to re-draw the amount of sockets within an object, raising or reducing it. You won't be able to use that item, if the amount of slots would be the maximum for a given item. Chromatic Orb - allows you to change the colors of the sockets in the merchandise. Orb of Fusing - allows you eliminating them or adding new ones. Vaal Orb - an item which allows you to modify an item randomly and apply the Corrupted parameter.

It's well worth recalling that it makes no sense to waste the above mentioned items on modifying low-level equipment. A much better idea is just to discover another, even worse in terms of parameters, thing which is going to have the sockets we need, and leave the things to be altered for later, to Path of exile currency for sale change in better gear.