"this is mainly for you Amanda, so it should be your choice first" Lisa assured her daughter. "we have to be the same mum" Amanda pointed out. "She's correct, anyone under legal adult age cannot undergo a permanent transmission unless accompanied by a parent or legal guardian and they must be the same transformation" Marcus explained. "I see" Lisa accepted before returning her attention to Amanda "still your choice while i'll handle the paperwork". "I'll get to looking then" Amanda accepted.
While Amanda was gone and Alice had returned with the required papers, Lisa quickly got to reading over everything while telling the two staff members the story of what led them here. "ouch... talk about a rough deal" Alice remarked in symphony. "will this affect our request's response?" Lisa meanwhile asked as she finished all parts except the transformation. "Well no and frankly this will most likely ruin that bastard's world domination plans... only thing of note is that I don't think the store can help your family members already 'lost' thanks to him" Marcus kindly admitted.
Just then Amanda returned "I've found the perfect choice" she joyfully announced. "it's brighten you up at least" Lisa accepted as she noticed what Amanda was carrying, a pair of mermaid costumes which consisted of single-dorsal fin tails with a lighter fin trail on either side up to the hips, elbow length scales gloves the same colour as the tail corresponding to them with lighter webbing between the fingers and fins on the forearm and finally the fact these tail costumes ended not at the waist as expected but instead at the neckline and ear-fin attachments. "? Something wrong mum?" Amanda asked. "are...are you sure this is what you want?" Lisa returned "I mean I know your a real lover of mermaids but these look nothing Disney like?". "I'm sure mum. besides other than their being no other types like i'm thinking your thinking about these ones are better suited for eternal time under the sea" Amanda explained.
"...alright. you win" Lisa accepted as she wrote mermaids as the transformation choice. "then you better check this one out first, got your size but I wasn't sure on colour" Amanda suggested as she handed Lisa the Green mermaid set while keeping hold of the purple one. "it's fine dear. isn't it?" Lisa pondered as she collected the set. "well like the Disney series the colour of tails isn't genetic though everything else in biology like hair and eyes is. so no, no problem" Marcus agreed.
Soon just outside the changing stalls "well... guess this is it" Amanda started in uncertainty. "you scared Amanda?" Lisa asked. "well yeah. but it's even more scary what'll happen if we don't do this" Amanda admitted. "oh before you go" Alice suddenly insisted as she rushed up "you're need to be aware of the transition period". "the what?" Lisa inquired "this a medical aspect?". "more a legal one. see for those choosing to undergo a permanent relocation like you two which requires the signing off of assists, it is not finalized immediately upon your transformation"Alice answered "if for whatever reason you change your minds or circumstances change within a month's time you can return to humanity with little issue and your assists returned minus costs that covers you like having spent the time spent like normal. after that though becoming human again permanently is often very complicated". "I understand" Lisa assured. "Hope you do well yourselves" Alice returned before remembering "oh one las thing. you need to say 'fac me ipso mihi somnium' once completely dressed to undergo the process". "right" Amanda agreed as she and her mother entered the stall.
"God these things are tight" Lisa muttered as she worked to pull the tail costume up over her chest. "meant to be worn without straps, what do you expect" Amanda returned having had Lisa's help getting hers on first and was now getting her gloves on after attaching the ear-fins while her mother sat down. "if these just went to the waist as you'd normally expect we'd either be going topless or in the upper halves of two-piece swimsuits" Lisa answered. "technically we will be naked" Amanda pointed out. "...good point' Amanda agreed.
soon after both mother and daughter were dressed and the clothes packed away to whatever the store did with them "soon to be the point of no return" Amanda announced. "outside of that Alice girl's statement... yes" Lisa agreed before asking "you ready?". "And waiting" Amanda answered before saying in sync with her mother "fac me ipso mihi somnium".
on sooner had the words been said there was a brief flash from the door cracks before the stall started getting slowly filled with water. while this was happening both Amanda and Lisa felt it as the costumes fused to their bodies, their lower bodies' bones painlessly altering from legs into tail bones, the scales of the former costumes becoming real scales alongside the fins while a membrane coated their eyes and their lungs altered by Amanda's guessing to allow them to breathe water which was soon proven as the water covered her head and she embraced the water passing through her body like air had once done.
"better get going then" Amanda called once the stall was fully submerged as she got up and swam to the door. "yeah... to the new undersea lives ahead of us" Lisa agreed as they opened the door to an amazing underwater realm where there were already merfolk going about among a series of caves like people back in the human world wandered the streets: