The best approach to mitigate the impact of a major life change on your dog is to prepare them far in advance of the change occurring. For example, with many people returning to the workplace after working from home for months, easing your dog into the change over a period of time may help. Unfortunately, for many, this is an afterthought and usually it is too late.
In a case like this, if you know you need to return to the office in a month or even a few weeks, you can begin to prepare your dog for the change. First, be clear about when your dog is likely to be left alone, and begin adjusting your current schedule very, very gradually to build up their tolerance. This is much better than simply starting work one day, and shocking your dog into panic because all of a sudden you are gone for hours at a time.
If you cannot do this then prepare to have someone look after your dog whilst you are out. For example, if your partner works from home make an effort to ensure they stay with the dog, enroll your dog in doggy day care or find a friend or neighbor who is willing to help. If your dog has developed separation anxiety gear yourself up to spend a lot of time helping him overcome his fears – resolving separation anxiety can take many months.