Replacing Grades suggestion

We plan to replace existing grades and would be renaming both the name and the code. Can you please suggest which is the best approach on the options below, or if there are additional options that we haven't considered, please let us know.

Options below:
1. Would you recommend us to just use the existing ones, create new effective date and replace the name and the code.
2. Would you recommend us to create new grades instead and assign them to positions. Inactivating the rest of the grades that were replaced.

Note we have position synchronization setup which we will run after the grade changes have been completed via HDL or HSDL.