Our Yorkie, Sophie, was pad trained up until 5 months, then we started the process of going outside.
I tried moving the pad closer to the door, but that didn't really seem to work for her. She would still go on the pad, but didn't get that we were transitioning to outside. So, I just started bringing her outside.
The first week was horrible. We would stand outside for at least a half-hour and nothing, then she'd come inside and pee in the house (sometimes on the pad, sometimes not!). I even brought her pad outside and she only went on that once.
Eventually, she started going outside and I would praise her tons! The following week we visited friends who had two dogs and I'd take her out with them and I think she saw what you do out there and caught on.
I also had success taking her out first thing in the morning when I would normally take her to her pad. I hadn't really crate trained her before this, but a week of crate training, 3-4 hours in her crate and then outside, play and back in the crate seemed to work.
She's almost 8 months now and not 100% house broken. She still has accidents from time to time, mainly pee and usually right in front of the front door or on her way there. But, she'll stand by the front door and wait or stare at me when she has to go. Now, she's good about doing both pee and poop outside and I think she prefers it too.
It may be harder with you living on the 17th floor, but I think it's worth training them to go outside, they are dogs after all and I got sick of my house smelling like dog pee and spending money on pads
It will be tough for a bit, but the summer is a good time to start. We started in February!!
Good luck.