If they're both current models, they both have a 1 1/8 inch threadless headset, so the fork should transfer as long as the fork's steerer tube is long enough to accommodate the bigger frame's longer headtube.

Can you take a few measurements before committing? Measure your current headtube, the bigger frame's headtube, and any headset spacers (above or below the stem). So long as the bigger frame's headtube doesn't exceed your current headtube plus spacers, you should be OK.