Replacing an old stove with a new range in a different location in the Kitchen. The old 4-wire service is too short to reach the new location. Can I put a junction box in the line and take a new wire from the junction box to the new stove? Or do I have to replace the wire with a longer wire from the breaker to ne stove?

Creehan,

What is the amperage of the existing circuit? What is the amperage required by the new stove?

If the wires are the right size, you could add a junction box, grounded, with cover and extend to new location.
Don't skimp on box size.