To understand the pattern:

• SYSTEM → SYSMET The 4th and 5th letters (T and E) are swapped.

• NEARER → AENRER The 2nd and 3rd letters (E and A) are swapped.

So, following this pattern for FRACTION:

• Swap 2nd and 3rd letters (R and A).
• Swap 4th and 5th letters (C and T).
• Swap 6th and 7th letters (I and O).

Resulting in: CARFNOIT