The phrase "has since requested" is correct and usable in written English.
It can be used to indicate that someone made a request after a certain point in time or event.
Example: "After the meeting, she has since requested additional information to clarify the project details."
Alternatives: "has subsequently asked" or "has afterward requested."
He first fled to Cameroon but has since requested refuge in Benin, news reports said Friday.
Mrs. Arafat has since requested that the French authorities open a murder inquiry, and on Sunday, Mahmoud Abbas, the Palestinian Authority president and Mr. Arafat's successor, said Russian experts would also be helping with the investigation.
Mr Snowden - who was also a contractor for the National Security Agency NSAA) - has since requested asylum in Ecuador.
"Donald Trump: The 'Apprentice' is a television smash!" TIME has since requested Trump stop displaying the fake cover.
Tan has since requested that Yale-NUS not show the film while she appeals the ban, hoping to reverse it.
Porsha -- who was reportedly "completely blindsided" by the filing -- has since requested alimony and asked that she be able to stay in their matrimonial home.
He said North Korea had since requested a further round of negotiations, which Haicheng Xiyang had refused.
Although my presence has since been requested at the table of many languages, and numerous people have invited me to sit beside them, I wish for no one else to have to do as I did, hacking at my own grave with a pick, in the hope that it was not yet ready for me.
He has since had requests to help Rhode Island, New Jersey, and the country of Spain do what Michigan did.
He has since declined repeated requests for interviews, and a spokeswoman for the hospital would not answer questions about the Patersons, other than to say that both had been helpful over the years.
