Without trust and rapport with your client, none of the techniques of NLP will work. You may tend to believe that there would be always some technique to plant an idea in your client's mind or to force a change. (Manipulation Fallacy). Unfortunately it does not work that way. Unless there is a deep trust and rapport with your client, your client will remain guarded which would defeat all efforts to help him.

You are not here to change people. You are not the boss. People change themselves. You are here to help. Unless you take this stand, NLP will fail for you utterly in the long run and your efforts will go to the dust.

Ultimately, you cannot influence a person whom you don't respect (or fake respect). The bottom line is that people don't like to be tricked cleverly.