It depends on how the company is set up.

If the total stock was allocated then it may be a tax issue to change.

The best option may be to have vesting periods that can then be accelerted based upon workload/responsibilities.

The other option may be to "contribute" stock into new corp or LLC, but again, looking at tax issues. I did this and it was not easy...

Or contribute assets (code etc) only (not stock) into new entity and close down the old company.

Or issue more shares enabling a vesting period (may be simplest thing).

Definitely consult with a qualified business accountant to avoid what could be major headaches and possible tax penalties.