Changing fingers while holding key down

[Knute Snortum]

Hi everyone,

In piano music, there's a technique for holding down a key with one
finger, then switching to another.  I know how this looks in music
notation (see attached) but I don't know how to engrave it with
LilyPond.  I've searched the docs, the LSR, and the internet for the
answer, but I don't know any technical term for this (is there one?)
so the results were less than helpful.

How is this done in LilyPond?  I'm assuming one uses markup with
\finger, but I can't find a way to make the "slur" on top of the
numbers.  (I've seen this notated with the slur under the numbers
too.)

--
Knute Snortum

change-finger.png
Description: PNG image