Use 'amiably' to describe actions showing good-natured friendliness in social interactions. Despite the disagreement, they continued to discuss the issue amiably.
Pro Tip 2/3
Amicable Atmosphere
'Amiably' often sets a scene where everyone is getting along in a comfortable and friendly way. The meeting proceeded amiably, with everyone in good spirits.
Pro Tip 3/3
Not Always Agreeable
Being amiable doesn't necessarily mean agreement; it's about the manner, not the content. He declined the offer amiably, without causing any offense.