It starts from the beginning, with:

• not making promises to never leave
• not fostering dependency by encouraging between session contact to process emotions
• making it clear that the type of therapy they practice does not focus on the therapeutic relationship (and if it does, then they do have an obligation to stick it out)
• apologizing
• admitting to not being skilled enough
• not blaming the client

And, if it's clear that to the therapist that she/he isn't skilled enough, to find a good referral and continue to see the client for check ins (like an MD would do).