Went through this issue a few months ago. Did the following:
1 - Signed-up for a Grand Central Number. This eliminated a huge problem, everyone not knowing what number to call me on. This consolidated my headaches and gave me a number that I controlled and not the company.
2 - Send an e-mail alerting everyone to the new number. I find that most people will change the contact information and dial from the contact rather than memory. Other than your parents, can you remember most peoples numbers? Have over 100 in my phone and can't remember half of them.