About delete a phone number.

[tumashu]

   phone: (work) 15076532xxx, (cell) 13775465xxx

How to only delete first phone number?

[girzel]

Just move point onto the number you want to delete, and hit C-k.

[tumashu]

Delete this `phone' field (of 冯书)?

Delete is a dangerous operate, I suggest message like this:

Delete `phone' 13775465937 (of 冯书)

[girzel]

Good idea.