N1
かたがた
Partly for (the purpose of), In addition to, Along with, By the way, And also to, Incidentally, While
婚約の報告かたがた、お父様とお母様に会いに行きます。
I'm going to see her father and mother, partly to tell them about our engagement.
Explanation
「Nかたがた」 means 'and also' or 'combined with'. When you go to visit someone, you use the occasion to take care of another courteous matter besides the main purpose. It appears in formal business letters and courtesy calls: 「本日はお礼かたがた、近況のご報告に伺いました」 (I have come today to thank you and also to report on how things are going). The noun is usually 「ご挨拶」, 「お礼」, 「お見舞い」, 「ご報告」 or 「散歩」, and the ending is a verb of going, such as 「伺う」, 「訪ねる」 or 「参る」. It is very polite and respectful.
Mixed up with
「〜かたがた」: the most elegant; for formal business and courtesy visits (thanks or greetings plus a visit).
「〜がてら」: everyday speech; doing something along the way during a walk, shopping, etc., e.g. 「散歩がてらパンを買いに行く」.
「〜ついでに」: casual; clear main and side matter, a small thing done in passing; not for a formal visit to a superior.
「〜かたわら」: doing a main and a side occupation over a long time, e.g. running a company while writing.