Can 220 v be spliced to make the wire longer in order to relocate the oven outlet?

Sure, providing the cable wire is of the same size conductor, quantity of conductors, splicing is done is an approved junction box of the correct size to handle the size and amount of wires being spliced, use the correct splicing connectors for the size and material wire being spliced, and the junction box is covered with the proper plate, and the junction box is left accessible.