Microchip details

[Bettythree]

Having just booked a holiday taking Bettydog with us I am now worrying about the contact details on his microchip.
We adopted him from a rescue a few years ago and they had him chipped with their details and put on the adoption paperwork that the dog must stay chipped to them for life.
since then the rescue has had various ongoing problems and i would be really unhappy if the dog were to be returned to them if he were lost. So can I change the details on his chip without their permission? I don't know who to contact to even ask - on the sticker with the chip number it says 'tracer advance pet identification system' but nothing else.
Any ideas?

I started a thread similar to this a we week's ago. I think the conclusion was you have to contact the rescue to add your details too?

Does your dog wear a collar and tag?
If you found a dog wearing a collar and tag, what would you do?
:)

If you contact pet log (they hold the chip register for tracer) you can apply to have the details changed to yourself. They will write to the currently registered owner if there is no objection within 28 days it will be changed to your details. There is charge for this.