One owner S-Corp qualifies for ERC. 100% shareholder took a salary.

Can the s-corp apply part of the ppp funds to the owner's salary and have less to apply to the qualifying wages?

PPP was $50,000, they used $20,000 of the ppp to pay the owner and the rest was used to pay the employees. 

Can the $50,000 forgiven PPP be reduced to thel $30,000 that was paid to the employees, or PPP funds can not be used against non qualifying wages.