1. to change; to alter; to revise; to replace
お忙しいのであれば、時間を改めます。If you're busy, I'll come back at another time.
2. to reform; to correct; to mend; to improve
そこで私は考え方を改めた。So I changed my way of thinking.
3. to examine; to check; to inspect
occ. 検める
早速中身を改めさせていただいても？May I go ahead and inspect the contents?
4. to do properly; to do formally
だから、改めまして、よろしくお願いしますね。So, let me say it properly: it's nice to meet you.