B1 contains an "old" value; C1 contains its "new" value
B47 contains an "old" value; C2 contains its "new" value
B93 contains an "old" value; C3 contains its "new" value
B139 contains an "old" value; C4 contains its "new" value

How do write a formula to replace the respective "old" values with
their "new" values?