Option 1:
1. Take the 4 train to Fulton Street.
2. Transfer to the A or C train.
3. Take the A or C train to 33rd Street.
4. Transfer to the 6 train.
Option 2:
1. Take the 4 train to Union Square.
2. Transfer to the N, Q, R, or W train.
3. Take the N, Q, R, or W train to 34th Street-Penn Station.
4. Transfer to the 6 train.
Please note that the specific steps may vary depending on the direction you are traveling. It's always a good idea to check the subway map or use a transit app to plan your journey precisely.