Ideally, yes - therapy requires a relationship of trust to be built between you and your therapist, and working with the same practitioner is advised to allow this to develop.
However, you are not obligated to continue working with the same therapist, and we also offer a guarantee to all of our clients, so if you meet with a therapist for an initial session but do not feel that they would be the best fit for you, we will offer to cover the cost of an initial session with a different therapist for you so you can find your best possible match. We have information about this option here.
It may also be that after working with a therapist for a period of time, you feel it would be best for you to start working with a different therapist instead so you can access other types of therapy or focus on different issues. We would recommend discussing this with your current therapist if you feel that it may be best for you to bring the relationship to a close, as they will be able to help with suggestions on other types of therapy that could be beneficial to you moving forward.