I was taught that prepositional phrases were essentially "expendable" components of a sentence that, while referring to the subject-predicate, are 'not really there.' In the context of the following sentence the author uses a

Hi All, I'm trying to reach somone(Senior executive) by phone, but with couldnt catch him so I will write the following email: Dear xyz Trust my note finds you well/ (or hope all is well) ?? I tried to reach you by phone via your secretary