The less personalised alternative should not be different or of degraded quality compared to the service provided to the end users who provide consent, unless a degradation of quality is a direct consequence of the gatekeeper not being able to process such personal data or signing in end users to a service. Not giving consent should not be more difficult than giving consent. When the gatekeeper requests consent, it should proactively present a user-friendly solution to the end user to provide, modify or withdraw consent in an explicit, clear and straightforward manner. In particular, consent should be given by a clear affirmative action or statement establishing a freely given, specific, informed and unambiguous indication of agreement by the end user, as defined in Regulation (EU) 2016/679. At the time of giving consent, and only where applicable, the end user should be informed that not giving consent can lead to a less personalised offer, but that otherwise the core platform service will remain unchanged and that no functionalities will be suppressed. Exceptionally, if consent cannot be given directly to the gatekeeper's core platform service, end users should be able to give consent through each third-party service that makes use of that core platform service, to allow the gatekeeper to process personal data for the purposes of providing online advertising services.