I want to merge specific line

Input :

```
AAA
BBB
CCC
DDD
EEE
AAA
BBB
DDD
CCC
EEE

```

Output Should be 

```
AAA
BBB
CCC DDD
EEE
AAA
BBB
DDD
CCC EEE

```

I want to search CCC and merge next line with it.

I have tried with awk command but didn't get success