John and Mary have been your client for years. You have handled their individual tax returns,

the tax returns for John's business, and their estate plan. John and Mary are going through

a divorce and their $20$XX married filing joint return has been selected for audit. You believe

that Mary may qualify for "innocent spouse" relief, which is when the IRS relieves a

taxpayer from paying additional taxes if their spouse understated taxes due on a

joint tax return and the taxpayer didn't know about the errors. Under Circular $230,$ can

you represent both John and Mary in the audit?

Sasha completed her client's tax return and gave him an invoice for the agreed$-$upon $$800$

tax return preparation fee. The client asks how long it took Sasha to prepare his return.

When Sasha tells him it took about two hours, the client refuses to pay the $$800$ fee.

Because an agreement cannot be reached between Sasha and the client over the fee

amount, Sasha returns the client's records, but she refuses to give him the completed tax

return. Under Circular $230,$ has Sasha violated her ethical duties?