so that, so as to, so as for

Hello. Can someone please help me with the following phrases (so that, so as to, and so as for) and how to best explain them to an ESL student. My thoughts are as follows:

So that is used with a noun or pronoun. For example, I am going to call her so that she knows I love her. Essentially one action will affect a noun or pronoun.

So as to is used with a verb. For example, I am going to speak softly so as to not disturb you. Essentially, one action will affect a verb.

So as for is used with a noun or pronoun. For example, So as for leaving tomorrow, the trip is off. Essentially, something is in regard to something else.

Thank you to any and all who can help me with this. I love this site!!!