If you specify that the minvalue is greater than the current value, there arises a contradiction.
Let us say that the current value is 100. You want to set the minvalue to 200.
The sequence has to start counting from its current value, that is, 100. What should the value be when the sequence is used?
Based on the current value, it should be 101. But that will be less than 200, the minimum value you specified.
Therefore, Oracle DBMS tells you it can not be done.
Since there is essentially zero overhead for sequences, just drop the sequence and recreate it.
Or, write a script to keep getting the next value of the sequence until the current value reaches your desired value.