I think a couple questions need to be asked before a solid answer can be given...

1) Why was this sales person hired to begin with? What was it about him/her that lead them to getting the job offer? Was it a hiring mistake from the beginning?

2) I'm sure there was product / service training, but what kind of sales technique training did the company put them through? Was the new hire expected to already know how to sell? I've seen people in sales for 20 years who still don't know the first thing about sales.

3) Are there other successful sales reps in the organization that this person can "shadow" for a few days? Someone who is playing on the same level field as the new rep?

If the sales rep was hired with the expectation that they were ready to go "out of the box" and only product / services training was needed, and they are failing to meet minimum benchmarks within the 30-60 day mark, a strong re-evaluation needs to happen asap.

As a small business owner who started in straight commission sales, I understand both sides of the coin.

My position is this: Hire slow and fire fast.

Just make sure your internal processes (hiring / sales training) isn't part of the problem (and if it is, fix that first) Otherwise this costly cycle will continue with new faces.