N1
ものとして
Assuming, Supposing, (Interpret) as, On the assumption, Regarding, Considering
みんなが参加できるものとして計画を立てましょう。
Let’s make a plan on the assumption that everyone would be able to attend.
Explanation
「〜ものとして」 means 'on the assumption that ...' or 'treating it as ...'. The situation is not fully settled, so to keep work moving you assume something is so and proceed: 「出席の返信がない方は、欠席するものとして扱います」 (Anyone who has not replied will be treated as absent). It appears in rules, manuals, contracts and meetings to say that a case counts as a certain state. It is formal and written.
Mixed up with
「〜ものとして」: formal and official; assume it holds, then carry out the procedure.
「〜つもりで」: the speaker's own mental pretending, e.g. 「死んだつもりで頑張る」 (work as if my life were on the line).
「〜とみなして」: a firm legal or judgment-based ruling, 'regarded as'; lacks the flexible working assumption of 「ものとして」.