Copying Phone Numbers from one Contact to Another

Has anyone found a way to copy phone numbers from one contact to
another? After transferring all my phone numbers from an old phone to
the SIMM card, and then from the SIMM card back onto the new phone,
any contacts with multiple phone numbers were broken out into multiple
listings (Steve, Steve1, Steve2, etc.) I want to re-group the phone
numbers and was looking for an easy way to copy the phone number from
'Steve1' into 'Steve' as a mobile number without retyping it. Any
thoughts?

-Stuart