It is definitely plausible.
Most importantly, the domestication should be the result of a symbiosis between the species. A mutually beneficial relationship that naturally develops.
In my mind I would say a few prerequisites should be established to help facilitate this symbiosis, primary of which is that the two species should live in close proximity, allowing for a historical familiarity of sorts.
An example of a plausible scenario would be:
Species A (raptor) and Species B (canine) have a common prey, and this prey is abundantly available in their common environments. Given enough time, multiple encounters between the species would likely occur simply by happenstance; hunting the same prey on the same grounds at the same time. Given even more time, these happenstance encounters would eventually yield an opportunity for them to observe that working together during a hunt yields better results (likely the first few times they would observe this by accident). And with yet even more time, this learned behaviour is reinforced through multiple situational / happenstance encounters. Add in little details like if the common prey were large and/or dangerous to hunt, would even better reinforce this cooperation. Naturally, the sentient species' ability to craft and think (assuming they are significantly more intelligent or advanced) and the canine species strength and transportive qualities, yields great cooperative opportunity. What may start as a cooperative arrangement with tentative commitment from both sides, again given enough time, will eventually become a much stronger symbiosis as long as the positive results are maintained over a significant enough number of generations.