Fit Curve is the essential tool for re-parameterize an existing spline.
To fit a surface, there seems to be two commands: Refit Face and Fit Surface. Since Fit Surface does not accept an existing surface as input, the choice for reparameterizing a heavy surface seems to be Refit Face.
And to reparameterize a surface, Refit Face directly edits the orginal surface, but Fit Curve creates a separate associative curve. The mode of Fit Curve seems to be better. [ADD: In this aspect Refit Face > Fit to Target seems to be similar to Fit Curve.]
I'm curious about why the two surface fitting commands are not merged together. Are there any key difference between their mechanism?
Thank you for your comments!