<human>: Give me the gist of the text in a nutshell

Hi, I already posted this in r/Calgary, but then realized that this might be a more appropriate place to make my inquiry.

 I need advice about moving from an apartment that I started renting from a management company back in March, into buying a condo. I found a condo that I am very interested in purchasing, and would need to make an offer on it soon.

However my apartment lease is not over until the end of April next year (14 month lease). This afternoon I stopped in to my rental office to inquire about breaking a lease early - I said that I had some reasons why I am looking at moving out early, but I would comply with any notice they require, and also my brother has expressed interest in taking over my lease for me. If he doesn't meet their requirements, I would be totally happy to find another tenant to move in so there was no loss of income for them. I want to be as cooperative as possible, and I figured there must be some way to go about this without penalizing anyone and nobody losing money.

I was told flat out "no, we do not allow lease takeovers. Your only option would be to pay a month's rent, plus a $100 concession for every month you've lived here". I told them I already had a few people who would be interested in moving in and taking over, so they wouldn't lose any rent, and they still said no.

I looked it up online and found out that what I meaning to ask for is a "lease assignment", and in Alberta it seems that a landlord can only refuse this for reasonable grounds, and cannot charge any fees for this. I couldn't find any other information in the Residential Tenancy Act that would clarify what "reasonable grounds" are, so I don't know how to go forward with this. Can someone please clear this up for me, or explain to me if my landlord company is allowed to say no at this time without an explanation?
<bot>: Please clarify what "reasonable grounds" means, in regards to a "lease assignment", and how my landlord can or cannot refuse a lease assignment if I find another tenant to take over my lease before it ends.