#include <bits/stdc++.h>
using std::bitset;
using std::cout;
using std::deque;
using std::endl;
using std::greater;
using std::lower_bound;
using std::make_pair;
using std::map;
using std::max;
using std::min;
using std::multimap;
using std::multiset;
using std::nth_element;
using std::pair;
using std::priority_queue;
using std::queue;
using std::reverse; 
using std::set;
using std::sort;
using std::sqrt;
using std::stable_sort;
using std::string;
using std::swap;
using std::unique;
using std::upper_bound;
using std::vector;
typedef long long li;
typedef long double lf;

inline li read(){
	li ans = 0, f = 1;
	char ch = getchar();
	while(ch < '0' || ch > '9'){
		f = (ch == '-') ? -1 : 1;
		ch = getchar();
	}
	while(ch <= '9' && ch >= '0'){
		ans = ans * 10 + (ch ^ 48);
		ch = getchar();
	}
	return ans * f;
} 

li n, m;
char a[110][110];
queue<pair<li, li>> q;

bool isfull(){
	if(q.size()) return 0;
	for(li i = 1; i <= n; i++){
		for(li j = 1; j <= m; j++){
			if(a[i][j] == '?'){
				a[i][j] = 'B';
				q.push({i, j});
				return 0;
			}
		}
	}
	return 1;
}

char change(char x){return x == 'W' ? 'B' : 'W';}

bool check(li x, li y){
	if(x <= 0 || y <= 0 || x >= n || y >= m) return 1;
	li cnt = 0;
	for(li i = x; i <= x + 1; i++) for(li j = y; j <= y + 1; j++) if(a[i][j] == '?') cnt++;
	if(cnt > 1) return 1;
	if(cnt == 0){
		return a[x][y] == a[x + 1][y] || a[x][y] == a[x][y + 1] || a[x][y] != a[x + 1][y + 1];
	}
	if(a[x][y] == a[x + 1][y + 1]){
		if(a[x + 1][y] == '?' && a[x][y] != a[x][y + 1]){
			a[x + 1][y] = change(a[x][y + 1]);
			q.push({x + 1, y});
		}
		if(a[x][y + 1] == '?' && a[x + 1][y] != a[x][y]){
			a[x][y + 1] = change(a[x + 1][y]);
			q.push({x, y + 1});
		}
	}
	if(a[x + 1][y] == a[x][y + 1]){
		if(a[x][y] == '?' && a[x + 1][y] != a[x + 1][y + 1]){
			a[x][y] = change(a[x + 1][y + 1]);
			q.push({x, y});
		}
		if(a[x + 1][y + 1] == '?' && a[x + 1][y] != a[x][y]){
			a[x + 1][y + 1] = change(a[x][y]);
			q.push({x + 1, y + 1});
		}
	}
	return 1;
}

int main(){
    // freopen("wonderful.ans", "r", stdin);
    // freopen("www.ww", "w", stdout); 
	li T = read();
	while(T--){
		n = read(), m = read();
		while(q.size()) q.pop();
		for(li i = 1; i <= n; i++){
			scanf("%s", a[i] + 1);
			for(li j = 1; j <= m; j++) if(a[i][j] == '?') q.push({i, j});
		}
		li fl = 1;
		while(fl && !isfull()){
			while(q.size()){
				auto u = q.front(); q.pop();
				// cout << u.first << " " << u.second << endl;
				if(!check(u.first, u.second)){
					fl = 0;
					break;
				}
				if(!check(u.first - 1, u.second)){
					fl = 0;
					break;
				}
				if(!check(u.first, u.second - 1)){
					fl = 0;
					break;
				}
				if(!check(u.first - 1, u.second - 1)){
					fl = 0;
					break;
				}
			}
		}
		if(!fl) puts("NO");
		else{
			puts("YES");
			for(li i = 1; i <= n; i++){
				for(li j = 1; j <= m; j++) putchar(a[i][j]);
				puts("");
			}
		}
	}
    return 0;
}