The executive rumblings that shook up channel leadership at unified communications stalwart ShoreTel Inc. are apparently reverberating all the way to the corner office.

The Sunnyvale, Calif. vendor announced today that CEO Peter Blackmore will retire as soon as a successor can be found. Blackmore, a sales leadership veteran with stints at Unisys Corp., Hewlett-Packard Co. and Compaq Computer Corp., took the chief executive job at ShoreTel in December 2010.

No reason was given for Blackmore’s departure in a brief official statement announcing the change.

“I am confident that the company is well-positioned in both the cloud and premise unified communications market,” Blackmore said in the statement. “With recent changes to our organizational and cost structure, we can now scale with a model positioned for profitability, enhancing our objective of delivering improved shareholder value.”

ShoreTel board chairman Chuck Kissner said he was grateful for Blackmore’s decision to “continue in his role during this transition period.”

“We intend to keep moving full speed ahead with our near-term plans to launch new innovative products and services and to continue to execute on our combined premise and cloud strategy,” Kissner added.

ShoreTel officials said a search for a new CEO is underway.

The CEO shakeup comes just weeks after ShoreTel lost its channel chief, Joe Vitalone, to an arch competitor. After a surprise exit from ShoreTel, Vitalone was introduced in March as the new executive vice president of sales for the Americas at Canadian UC specialist Mitel Networks Corp. in Kanata , Ontario.

ShoreTel is about a year into a significant channel revamp aimed at better positioning the vendor against a growing number of UC competitors, particularly in the cloud.