The phrase "an earlier request" is correct and usable in written English.
You can use it when referring to a request that was made previously in a conversation or correspondence.
Example: "I would like to follow up on an earlier request regarding the project timeline."
Alternatives: "a previous request" or "a prior request".
A music publisher had denied an earlier request, days before opening night.
Banks came up empty-handed in response to an earlier request to locate Mr. Milosevic's funds.
The Ministry of Justice was not able to respond to an earlier request for comment.
Last fall, the state, without explanation, dropped an earlier request to seek the death penalty.
The UK government refused an earlier request to allow Assange safe passage for hospital treatment.
With the encouragement of Joint Chiefs of Staff chairman Gen. Earle Wheeler, Westmoreland renewed an earlier request for more troops.
3.34pm BST Before we start, an early request from the man at the toppermost of the MBM poppermost, Gary Naylor.
Gov. Jeb Bush refused today to allow an early request for clemency of a 14-year-old boy sentenced to life in prison for beating a 6-year-old girl to death.
Matthews said he agreed to an early request by City of London police to upgrade the postmortem to a "special examination" – a form of autopsy conducted in suspicious deaths.
I'd like to table an early request to get the band back together, because I'm not sure I can take any more of those tiny, brittle cracks appearing on Saga's magnificently impervious face.
But the response to an early request for development proposals was inconclusive, and the island's operating corporation decided to open the island to visitors each summer, moving ahead first with building a fan base, then with an open-space competition, and now with the construction of that new landscape, all without a hotel, university, or museum in place.
