请帮我解决以下问题
source spark dataframe - ：
+---+-------+-------+
|key| city|flag |
+---+-------+-------+
| 1| Noida|active |
| 2|Gurgaon|active |
| 3| Delhi|active |
+---+-------+-------+
目标火花数据框 - ：
+---+-------+------------+-------------+
|key| city|sarogate_key|flag |
+---+-------+------------+-------------+
| 1| Noida| 1|active |
| 3| Delhi| 3|active |
| 2|Gurgaon| 2|active |
+---+-------+------------+-------------+
在源火花数据框中，密钥1城市从诺伊达变为孟买
+---+-------+-------+
|key| city|flag |
+---+-------+-------+
| 1| Mumbai|active |
| 2|Gurgaon|active |
| 3| Delhi|active |
+---+-------+-------+
现在我们需要将目标火花数据框更改为以下格式并保留历史记录
+---+-------+------------+-------------+
|key| city|sarogate_key|flag |
+---+-------+------------+-------------+
| 1| Noida| 1|de-active |
| 3| Delhi| 3|active |
| 2|Gurgaon| 2|active |
+---+-------+------------+-------------+
| 4 | Mumbai | 4| active |
+---+-------+------------+-------------+