You probably should still read the full article because it has many more details and explanations!
That said, at different times in your career, you'll definitely need different kinds of support and representation.
Be grateful and recognize the important role your current gallery has played.
And, most importantly, treat them with respect - even if they haven't treated you that way! ;-)
By taking the higher ground, you set the tone for your own career and how you will be perceived.
Here's to smooth and "amicable" gallery break ups! ;-)