CSV to Text File Conversion

I need a two-column Excel created CSV file converted to a continuous text file. The format should be: EXCHANGE:TICKER, EXCHANGE:TICKER, EXCHANGE:TICKER,

Requirements:
- Input: Comma-delimited CSV
- Format: Uppercase letters for exchange and ticker symbols
- Handle invalid/missing entries by skipping them

Ideal skills and experience:
- Proficiency in handling CSV files
- Familiarity with text file manipulation
- Attention to detail to ensure accuracy