The phrase "an existing client" is correct and usable in written English.
You can use it when referring to a client who is already engaged with a business or service.
Example: "We need to prioritize our resources to ensure that we provide excellent service to an existing client before taking on new projects."
Alternatives: "a current client" or "an active client".
Mr Prazan speculated that the buyer, an existing client, would not have bought it at his gallery.
Chauffeurs could sign up for as many or as few hours as they wanted, and they could log off if an existing client came calling.
If (and only if) you have the support of the group then the main benefit is speed, as you have an existing client base and talent pool; plus there's no need to raise venture capital.
Anyone with a recommendation from an existing client can call a number and wait an hour or so for a clean-cut young man to show up, probably on a bike, with a backpack of different varieties.
Scout Analytics' current customers include the Financial Times and Reed Elsevier, as well as information services company Wolters Kluwer, which is also an existing client of ServiceSource.
With an existing client roster that includes such leading brands as eBay, Google, and Expedia, Essence looks to continue its global expansion to offer best-in-class digital marketing on a worldwide scale.
Stage 1 of the Recovery model was implemented in October 2010, and involved reallocating all existing clients to an appropriate team based on case complexity, and reallocation of claims managers to new functional roles.
MSI gains access to an established clinic and existing client base in a community when we invite new members to the BlueStar network, obviating the need for the startup costs and effort associated with opening a new MSI clinic.
Their duties include retrieving patient history when an email was from existing client, auditing client emails to ensure all incoming emails had been answered and the manual provision of workload data for management reports.
BGR Gabara sent an email a week later declining the business, on the grounds "that by virtue of taking on the Uzbek account we would do a disservice to our existing client, the government of Kazakhstan.
"We're not dependent on new clients because we plan to grow within our existing client base," says Verdaguer, 50, an electrical engineer.
